I only know of 3 - Tentacle Locker which is basically a mini-game, and two RPGmaker ones whose names I forget - One of them was quite recent, the other is at least 5 years old by now. I guess She Ill Server kinda counts, you summon among other things tentacles against the NPC girls. There are a couple more games like that but nowhere near as good (imo) floating around.
There's also Pretty Warrior May Cry, a recent RPGMaker game by Mugcat and another RPG whose name I forget that do the whole "design a dungeon" type thing.
I'll look up the names to a couple of these when I get the chance