My first ideas for custom warscrolls:

• Warlock apprentice: 4 wound character. Warplock hellbard. Not a wizard, but can dispell one spell per round as a wizard.
• Mechanical rats: Melee unit. Wolfsize rat robots. Bases on the warscroll of Direwolves
• Warp Golems: Melee unit. Size between clanrat and rat ogre. 2 or 3 wounds. Not a killer but decent in combat.

More to come.