I was really bored, so here is a random kit concept (which is not good to use but it is funny)

When you die without a bed, you don't immediately lose the game. Instead, you spawn a zombie which you spectate and the match only ends once it dies.

If you have leather armour + stone sword, you spawn the leatherchest zombie, which has a large amount of hp, but doesn't move much and has a bow with good accuracy but a long cooldown. This zombie is intended to be bad and spawns 20 blocks near where the player dies (the other zombies spawn at the team generator).

If you have iron armour + iron sword, you spawn the screendoor zombie, which has an iron sword (but its AI and extra range gives it an advantage compared to a player) and a screendoor which is basically an emerald shield. The easiest way to defeat it is knocking it into the void, towering or blocking it.

If you have diamond armour + diamond sword (or crossbow), you spawn the ladder zombie, which has a diamond sword, shears (good at breaking blocks) and infinite ladders. Whenever it falls, it pathfinds to the nearest wall and does a ladder MLG. Ladders are invisible and don't affect players, but you can't suffocate the ladder zombie because it destroys any blocks placed on it.

  
If you have em armour + em sword (or headhunter) + enchant, you spawn the giga-gargantuar. He has 2 phases. In the first phase, he spawns at the team generator and attacks with an emerald sword. He keeps any enchants that the player has + cloud enchant and tries to rush the player before they can get enough gear to defeat it. When he is defeated, he teleports to the titan spawnpoint and regens to full health. He has a cannon that rapidly fires leatherhead zombies everywhere, with a max count of 20. He has extremely high knockback with melee attacks.

Random kit concept because I am bored (based on PvZ, I call it the necromancer)