An idea I just had (inspired by a recent video on Among Us suggestions) was to give imposters the ability to set traps to stun crewmates.
When the imposter isn't near a crewmate, the kill button would be replaced with the Trap button, and the nearest task location would be highlighted. Pressing the Trap button would set a stun trap on the highlighted task, affecting the next crewmate to attempt to perform a task there. That crewmate is stunned and blinded for 10-15 seconds, and the imposter receives a notification that the trap was triggered. However, ghosts can see trapped tasks and attempt to Block the sabotage, hovering over the task. If the trap would be triggered while a ghost is blocking it, the trap is triggered and removed with no effect (though the crewmate still knows the trap was triggered, and the imposter gets a notification that their trap was disarmed). An imposter has a 10 second cooldown on setting traps, and the traps last until triggered, potentially persisting through meetings. Optionally, ghost imposters may be given the ability to set traps as well, although with a longer cooldown.
The trap mechanic would allow the imposter to slow the game down, gather information, and pull off interesting mindgames, but it also gives ghosts something to do that doesn't completely break game balance. This mechanic would probably work best as either a game option or as a mod.