For April Fool's Day, I thought it would be fun/funny to make drafts of subclasses designed to fulfill the opposite of the class design. Obviously these are very thrown together subclasses with no playtesting and no balance changes, so use them at your own discretion! I also decided after writing a few that I'm going to release them one by one.
Cleric Domain of the Godless
Somehow, you've awoken a force inside, some great gift from...well you don't believe in the Gods of course, but from somewhere, right? Just not a God. Maybe you're really a warlock, or a wizard who finally had something click, but no that's not it either. There is no pact. There is no spellbook. It's just you, and this awesome power for no reason. Best not to ask questions about it.
Godless Domain Spells
You didn't actually think having no divine support would yield MORE power, did you?
There is no deity granting you extra power.
Godless, might as well be spell-less.
Alone In The Cosmos
Starting at 1st level, you have no divine explanation for your power, nor do you believe in anything divine or otherworldly. You are unable to have proficiency or expertise in the Religion skill, and make all Religion checks with disadvantage.
Not To Me They Don't
Because you are so unaffected by deific powers, you gain resistance to two types of magical damage of your choice from: Acid, Fire, Cold, Lightning, Radiant, and Necrotic. In addition, any damage that you would deal of those types is reduced by half (before applying other resistances and immunities).
Channel Divinity: No One To Call Upon But Me
At 2nd level, you can use your Channel Divinity to invoke your own power, not needing anything from any deity.
As an action, you present your self-righteous symbol and a wave of underwhelming force seems to wash over friendly creatures. For one minute, any friendly creature within 30ft. of you may use one of your own ability scores when calculating results of a roll. Friendly creatures may only use this feature once on each of their turns.
No Afterlife For Me
At 6th level you have affirmed your beliefs, and thus nothing will happen to you when you die. When you would drop to 0 hit points, you cannot be healed, or benefit from items or other effects that would cause healing or stabilization. As a result, when you die, you cannot be resurrected in any way, shape, or form. However, you also gain advantage on death saving throws, because no one is going to help you but yourself.
Who Needs Divine Intervention When You've Got Mad Skills?
At 8th level you're really pushing on those deities that do exists buttons. You gain your Divine Intervention feature two levels early, because it's not divine intervention, it's just you trying harder. It's also called Mad Skills now, so you don't have to even mention the divine.
Beginning at 8th level, you can call upon your motivation and effort to try a little harder when you need to.
Imploring yourself to do better uses your reaction. When you would roll any dice, and use this reaction, select a Skill most appropriate for the roll, or use Nature in the case of disputes, and add your Skill modifier to your roll.
You can use this feature whenever you want, as many times as you want, but keep in mind that everyone else who believes in the deities probably isn't wrong, and eventually your GM is gonna smite you to stop this from happening. You don't have to believe you've been struck by divine lightning, but you do have to suffer the damage.
At 20th level, when you use this feature, select instead your highest skill modifier and give yourself expertise for the duration of the roll.
All Powerful Aetheismo
At 17th level, you have become the closest thing to a God that you are able to conceive of. Your Channel Divinity: No One To Call Upon But Me is now always active, and you can make use of one of the friendly creatures ability scores in this way as well. This does allow for you to, for example, borrow the Barbarians strength, and allow someone else to then borrow that ability from you.