>>95891972 (OP)I once ran a Ravenloft game in a setting homaging Mask of the Red Death, with 7 noble families trapped in their palaces, their domains each plagued by one color of slaad.
Each year the beleaguered nobles gather at a masquerade thrown by Prince (the Dreadlord, whom was a monster in life notorious for abandoning and aborting unwanted bastards).
At this ball, the Slaad Lords of the Demiplane demand the Prince feed the most virtuous guests tadpoles so that they might be the start of the next generation to torment their families in exchange for keeping him in power.
And so it goes ad infinitum.
Can't overstate how fun Slaad proved to be as the 'core enemy type', especially if the players aren't familiar with them before hand. Watching people get shocked and freaked out by how actually scary they are never got old.
Unrelated, I played in a Pathfinder game where a few Boggart clans proved essential to our party's saving of the realm and they were a riot from start to finish. As fun to fight as they were to manipulate.