Disclaimer: The way that my ranking systems are set up is based specifically off of my personal opinion and their utility from a usage perspective in a traditional campaign setting. I view a traditional campaign as being one part roleplaying, two parts adventure and two parts combat. While your ability to roleplay based upon a particular selection will be taken into consideration, I always find that in DnD you can justify roleplaying specific ways despite your subclass. Some people may call that power gaming, but the point of DnD is to be challenged, have fun and stay alive despite the odds. If you die because you want to be cute and gimp yourself, you just failed on two of those. These ranks are also heavily weighted to abilities that are granted prior to level 15 as the vast majority of campaigns end before you reach that point.
With that being said, Divine Domains are all viable unlike some options with other classes. None of these will severely gimp you as clerics are generally quite powerful - particularly at lower levels. Some are simply, and unarguably, better than others.
There are four things that separate each domain from one another; Domain Spells, Channel Divinity, Domain Features & Additional Proficiency, if any. Domain Spells are free prepared spells that you receive at levels 1, 3, 5, 7 and 9. These are prepared for free but they are not free to cast and will still cost you a spell slot when used. Some of these come from a different caster spell list which provides a lot of versatility. Channel Divinity is something that every cleric acquires at level 2 and can be used once per short rest. While every cleric gets Channel Divinity: Turn Undead, some Divine Domains have Channel Divinity that is circumstantially game changing. Domain Features are extra abilities that you get at certain levels due to the Divine Domain that you have picked. These vary wildly based upon your selection. Some Divine Domains get an additional proficiency in martial weapons and/or heavy armor which should not be under estimated.
These are broken into three tiers; The Acceptable, The Good & The Amazing.
The Acceptable
12: Knowledge
Play this if you're a smarty pants but not intelligent enough to pick wizard
While I did say that all cleric Divine Domains are viable and will not gimp you, this one comes dangerously close. It is tough to justify taking it beyond desperately wanting flavor, in which case you're better off going with an Arcana cleric or a Divination Wizard. First things first, you are essentially a full caster cleric with no increased survivability. This in itself is not bad, but this domain strangely comes with an added proficiency; martial weapons. This is mostly useless for this domain.
There is a lot of flavor here with spells like Augury, the ability to Read Thoughts with your Channel Divinity and the ability to magically be able to learn a new skill over the short term; however, aside from the 8th level Potent Spellcasting you get nothing but flavor. With Potent Spellcasting you get to add your Wisdom modifier to your cantrip damage. A neat trick, but not particularly powerful at the time you get it. You have better things to do than cast cantrips.
11: Death
Play this if you want to be emo and you like under powered necromancy.
I like to call this Divine Domain “Grave Light”. It is thematically similar but nowhere near as powerful as the Grave domain. You are old school emo by default which is not necessarily fun to play. You are proficient in martial weapons but you do not receive heavy armor proficiency. You do, however, get Touch of Death which is your Channel Divinity that allows you to deal 5 + twice your cleric level necrotic damage on a melee attack. In the opposite direction as a pure caster, Reaper allows you to target two combatants with your Necromancy cantrip instead of one. At 6th level you ignore resistance to necrotic damage which is marginally helpful.
A few of the spells that you get by choosing this domain are also valuable and not available to other clerics; Vampiric Touch, Blight & Cloudkill.
10: War
Play this if you forgot the much better Paladin was available.
Optimistically, this domain comes with heavy armor & martial weapon proficiency. It also has a pretty solid 6th level Channel Divinity with War God's Blessing. This allows you to provide an ally with +10 bonus to their attack roll which is a pretty huge deal. Unfortunately, after those two points the domain drops off significantly and it doesn't offer enough distinction in my eyes from a roleplaying or even a combat perspective.
The base cleric class already has access to nearly every Domain Spell that War comes with. The exceptions to the rule are low level and Paladin spells which are a bit under powered. Even your Divine Strike is non-magical. If you want to play a War Domain cleric, just play a Paladin instead.
9: Nature
Play this if you like hiking but you do not want to be a ranger or a druid.
This is another flavorful Divine Domain but it has a much better taste. You can imagine a Nature Domain cleric is a wannabe druid or a better ranger. You get a number of thematic spells like Animal Friendship, Speak with Animals, Spike Growth & Plant Growth. You also get to learn a single cleric cantrip which can be great for roleplaying, added utility or do some extra damage. A very interesting possibility here is Shillelagh which would allow you, with your heavy armor proficiency, to become a better melee combatant.
The stand out with this Divine Domain is a proficiency in heavy armor and Dampen Elements. With Dampen Elements, starting at 6th level you get to use your reaction every round in combat to provide resistance to acid, cold, fire, lightning or thunder damage to a single creature. This can keep your tank alive a lot longer or save the life of a squishy companion. The fact that this is a simple reaction means you get to utilize it almost constantly.
The Good
8: Trickery
Play this if you really wanted to play a rogue but your party needed a healer and someone else was already a rogue. Or if you really liked the film Multiplicity.
Everything in DnD is DM dependent, but this takes the cake in terms of Divine Domains. The Trickery Domain has some abilities that are both functional and unique. You get a number of very valuable, though sometimes situational, Domain Spells like charm person, disguise self, mirror image, polymorph and dispel magic. If you have a stealthy scout in your party, Blessing of the Trickster allows you to functionally grant them advantage on stealth checks indefinitely.
Beyond the powerful spells that you get with this domain, the fun theme and your first level perk; you get Channel Divinity: Invoke Duplicity at level 2 and Improved Duplicity at level 17. Invoke Duplicity allows you to create a duplicate of yourself that can cast spells and confuse your enemies into attacking it instead. Improved creates up to four duplicates of yourself and sounds like a nightmare to DM. No additional proficiency here.
7: Order
Play this if you like bringing evil-doers to justice and protecting your party.
The Order domain is thematically fascinating to me though I have yet to have a single player in any of my campaigns or one shots play one. I fail to see why. While you do not gain proficiency with martial weapons, you do get access to heavy armor. You are a party buffing monster that can sit in the middle of a fight and soak up damage while fighting for law and justice!
Right from level one you get Voice of Authority which allows an ally to use their reaction to make an additional attack when you target them with a spell. While there is nothing overpowered in the Domain Spells, you get a lot of tools to play with. When you reach 6th level you also get Embodiment of Law which grants you the ability to use enchantment spells as a bonus action instead of a normal action. A great combination that instantly springs to mind is Hold Person combined with an attack or cantrip against the paralyzed foe.
6: Arcana
Play this if you want to be a wizard that can heal with free Dispel Magic every time you do.
Imagine having access to wizard cantrips and high level wizard spells, but you're wearing medium armor and a shield. Now call yourself an Arcana cleric. The down side to how amazing this sounds is you do not gain access to those high level spells until you reach level 17. With that being said, you are a spell casting machine with a lot more utility before then and you get the cantrips at level 1. At level 5 you gain the ability to flat out banish celestial, elemental, fey or fiend creatures as a Channel Divinity as well.
When you reach 6th level you gain the ability to functionally cast Dispel Magic on any ally you are healing. Imagine your party member is charmed and also low on health. You just solved both of those problems in a single turn, effortlessly. There is a lot to love about this domain and the icing on the cake is adding your wisdom modifier to any cantrip you cast, including the wizard cantrips you have, with Potent Spellcasting starting at level 8.
5: Forge
Play this if you want to create magical items at level 1 and start bashing skulls right when you're done.
This domain is a solid selection right from the start. You immediately gain access to heavy armor and Blessing of the Forge. Blessing of the Forge allows you to grant a +1 bonus to AC to a piece of armor or a +1 bonus to attack and damage rolls on any weapon. You can also get very creative with Artisan's Blessing that allows you to craft items from other materials, but I will not give you spoilers on that.
This domain comes with a solid spread of spells as well. My two favorites are searing smite which helps you deal significantly more damage as a melee combatant and wall of fire which has a ton of utility along with being a great aoe damage spell. Top this off with Soul of the Forge at level 6 which grants you resistance to fire damage and an automatic +1 bonus to AC while wearing heavy armor and you are one tough character to take down in a fight.
The Amazing
4: Life
Play this if you want to be the greatest healer that ever lived but also be a tank.
Yes, you are mostly a one-trick pony. Yes, it is an amazing trick and you do it phenomenally well so everyone will love you. This is the one domain that I am indifferent to it not receiving unique Domain Spells. The Domain Spells that you get with Life Domain are all the best spells you were going to take any way for each level, so this frees you up to be creative and expand upon your efficacy. Once again, you also gain access to heavy armor so you can be in the thick of things and hardly notice.
You are not just great and keeping everyone alive around you, you also gain the ability to seamlessly heal yourself while you are healing others with Blessed Healer at level 6. When you cast a healing spell on a fellow adventurer, you automatically heal yourself for 2+ the spell's level every single time without limit. At your very first level you already get an additional 2+ the spell's level hit points of healing to whomever you heal every time you cast a healing spell. A great example of this is casting 3rd level Mass Healing Word at level 6. You heal up to six creatures for 1d4 + WIS modifier + 3 (spell level) + 2 and you also heal yourself for a free 5 hit points to your own health pool.
If you're in a party of 5 you just healed for a minimum of 41 hit points (assuming 16 Wisdom). If someone in your party gets knocked unconscious or stays down for long, you were sleeping on the job.
3: Tempest
Play this if you want to wreak havoc in melee while controlling the weather.
This domain starts out strong and just keeps building. Right out the gate you have access to martial weapons, heavy armor and the ability to deal retaliatory damage to your foes as a reaction with Wrath of the Storm. Shortly thereafter, at the lowly level of 2, you can automatically maximize the damage dealt by your lightning or thunder spell as a Channel Divinity. With Thunderwave, one of your Divine Domain spells, that means you deal 16 damage to every creature in a 15 foot cube around you while simultaneously pushing them 10 feet away as a level 1 spell.
Later on when you reach level 6 all of your lightning spells also push your enemies 10 feet away which is incredibly useful in terms of battlefield control and can very readily help a squishy member of your adventuring group. The vast majority of your Domain Spells also come from different classes which provides you with a very unique play through as a cleric. Shatter, call lightning, icestorm and destructive wave are especially enjoyable. You even get to fly as your level 17 perk!
2: Light
Play this if you want to be an absolute wrecking ball with spells and plenty of added utility.
First and foremost, a Light cleric is a spell caster more than a melee combatant. Once you get over this fact and realize you are still difficult to kill nevertheless, you can embrace the fact that you are a damage dealing behemoth. What truly makes this domain shine is the Domain Spells, but first we'll look at all of the other perks.
At first level you get Warding Flare. This grants you the ability to impose disadvantage on an enemy that is attacking you. You get to do this as many times per long rest as your Wisdom modifier. Once you hit 6th level, this gets extended to any of your party members. You also get the ever helpful Potent Spellcasting that lets you add your wisdom modifier to any damage dealing cantrip. At level two you get a helpful Channel Divinity in Radiance of the Dawn that dispells all magical darkness and also damages every enemy within 30 feet of you.
Now on to the most exciting part; Domain Spells. You get some of the best wizard spells as a cleric. Burning Hands, arguably the best low level AoE spell, and Faerie Fire, arguably the best combat-utility spell at level 1. Scorching Ray is one of my favorite wizard spells and you get that at level 3. Then you get Fireball and Wall of Fire as well. Just imagine yourself throwing a fireball into a room then walking in with your Spirit Guardians. You are an AoE damage dealing beast.
1: Grave
Play this if you never want your party members to die under any circumstance.
This is the ultimate party member in my opinion. Imagine this domain as a panic button that simply saves lives left and right that also has a very dramatic theme. I find this domain to be very under rated likely just based upon the fact that it does not get heavy armor or gain access to martial weapons. With this domain, you are primarily a spell caster but you can still comfortably take a few hits. You do that spell casting job remarkably well, though!
The Domain Spells that you get are unique and themed toward a comprehension of the line between life and death. Much of this is utility but you get solid damage dealing spells in the form of vampiric touch & blight as well. From the outset thanks to Circle of Mortality you get to cast spare the dying as a bonus action with a range of 30 feet. If your friend goes down, they are not staying down for long either because you get to maximize your dice to restore hit points to anyone at or below 0 hit points, without limit and regardless to the spell level.
If this was not enough and you want to help your party members in other ways, with Channel Divinity: Path to the Grave at level 2 you can make any creature you see within 30 feet vulnerable to ALL damage the next time it is attacked. Some creative combinations here are your rogue friend's sneak attack or your paladin friend's divine strike. You get some great icing at 8th level with Potent Spellcasting, like the Life, Arcana & Knowledge Domains. When you hit level 6 you get Sentinel at Death's Door which functionally negates critical hits against your fellow adventurers. A number of times per day equal to your Wisdom modifier you get to turn a critical hit into a normal hit as a reaction on anyone within 30 feet. Not only is this a reaction; not only is this within 30 feet; not only do you get to do this multiple times per day; you also negate any effects triggered by the critical hit as well. Welcome to finishing an entire campaign with all the same friends.