I saw a mention of a possible idea on BGG from a long time ago, and I'm wondering if it's an idea worth exploring for fan cards.
The card suggested was something like "+2 cards. You may spend an extra action, if you do, trash up to 2 cards from your hand."
So in general, what about the idea of spending extra actions for a more powerful effect? Of course, in games without Villages, those more powerful effects could never happen, but that shouldn't be a problem (sometimes Conspirator and Tunnel just can't do what they're meant to).
I'm not sure of the ideal wording, as "spending actions" is not defined in the rules. But I think "spend an action" is probably the best way to phrase it. You could do -1 action (which I've seen on fan cards), but that doesn't make it clear that you have to have another action available in order to do the effect.
Also, this sort of thing really could only be on terminals; otherwise the whole thing could be rephrased as a choice where only 1 choice gives you +1 action. So it's basically like a "double terminal".
I guess the tricky thing would be how to balance how powerful the extra effect should be. It needs to be powerful enough that it's worth it in games where +actions are scarce, but it can't be too good, or else it's overpowered in games where +actions rampant.