I am currently working on some custom Green White and Black cards derived from an ability I saw called "Excommunicate" online.
I can post some up, and I'd like to see some other people's ideas for custom cards (Preferably fun and balanced for their intended format, not just Win cards)
The rules of Excommunicate are as follows
Excommunicate: Whenever this creature becomes blocked or is blocked, you may exile it. If you do, all creatures you control gain X (dependent on the card)
Excommunicate happens after declare blockers, and before damage, therefore implementing itself during damage.
I think it's fun, and although sounds crazy, it can be not too good, because in order to get the ability on everything, you need creatures, yet if you're Excommunicating them all, there are no creatures to effect. This makes the Combat Step of any game much more random and fun
Post your ideas!