Since there has been a lot of errata etc about some keeper cards are only allowed to play once, this is my suggestion for upcoming expansion.
base rule is:
*Keeper cards can never be played more then once preforming the exact same action.
(e.g not move the same monster twice. Not use UU on same investigator twice to move, but move and action is ok etc)
*Add a infinity marker on Keeper cards that can be played multiple times.
What do you think Corey?