Cryoxx,
Your game is great as is, so I don't see any real need to go crazy with lots of "out there" fetishes, but I agree with Pitrik. Most players of these games, myself included, wouldn't get excited seeing multiple males or futa with the LIs in your game. It would turn off many more people than would enjoy it. Devs should make the game they want, but unless you are really determined to add more other male (or futa) action, I would skip it.
If you feel the need to spice it up (more), the first 4 choices are fine and would not bother most players. Pet play is OK too, though I can take it or leave it personally.
For me, better than adding specific fetishes, is to add more varied characters to the game. You did a great job adding the giantess and her attendants, so including even more variety of body types and personalities, can be fun and add spice to your game.