When I DM I have a consistent house rule that if you have the ability to do a bonus action, you can do a strike with an unarmed off hand if you are adjacent to an enemy regardless of class. If it connects it does 1d4 bludgeoning and has a chance to knock a medium or smaller enemy prone if the player wins a strength contest. Nat 20 achieves both the connecting of the hit and the prone.

“Also, f*ck monks.”

I like when my monk players take 15 minutes to decide what to do only to end up punching a bunch of times and end their turn.