I tried to came up with a few of my own idea's so here they are :p
---Secret Kits---
Super Spiderman - SkyWars: A buffed version of the regular Spiderman Kit.
All the Leather Armour will have Protection II. An infinit Speed I or II Boost + Infinit Jump II Boost. 20 Cobweb.
Enchanted Golem - SkyWars: A buffed version of the regular Golem Kit.
All Iron Armour will get Protection I and the chestplate gets Thorns II. Also, you will receive a Poppy.
Green Arrow - SkyWars: A buffed version of the Archer Kit.
You'll receive 15 Arrows with a Power II Bow. You will also get non-enchanted Green dyed Chestplate and Boots.
Wizard Kit - SkyWars: A non-excisting Kit I came up with.
You will get a variaty of Potions and Splash Potion. (I'll let the Staff members think what Potion to balance this Kit). And a Purple Dyed non-enchanted Chestplate.
Horse Knight - SkyWars: Why risking getting shot off while walking on a bridge if you can ride a horse?
You'll receive a Horse with a Saddle ofcourse and 5 Hay Bales (Can be used for food). And 1 Golden Apple.
The Ban Hammer - SkyWars: Why not?
You'll receive a Blaze Rod with Knockback III or IV.
Egg Wizard - EggWars: It's called EGGWars and no Egg Kit so far?
You will get around 16 or 32 Eggs since I think 64 like in SkyWars would be OP since the other Teams couldn't build to mid anymore then.
Flyer - EggWars: For those who want to fly.
You'll receive and Elytra. Why won't this be TOO OP? The person first needs Sandstone Blocks in order to reach an island most of the times.
Ninja - MoneyWalls: For the sneaky people.
You get 2 Splash Potions of Invisibility, an infinit Speed I Boost and a Stone Sword.
Serial Killer - MoneyWalls: You get a REAL WEAPON.
You get a stone Axe with: Unbreaking I, Sharpness I, Bane of Arphotrops I and Smite I. Really nice for slaying Mobs!
Enderman - ControlPoint: Also for Sneaky People.
You get: Black Dyed Boots and Chestplate, 15 Chorus Fruit, an Eye of Ender with Sharpness II, Stone Pickaxe, 16 Brick Blocks and 2 Potions of Invisibility.