Help with Home brewing Bosses

I have been playing D&D for quite a long time and Me and a group of friends has been making custom campaigns, weapon, abilities, races, classes, etc. However, I have never done a completely custom boss. The only problem I have been having is getting a monster abilities list. I wonder if anyone has all the D&D boss abilities. If you could get that for me it would help a lot.

Do you mean monster abilities? It has them all laid out in the DMG.

Really? I didn't check that. Thanks for the clarification!