1- Ratchet x Rivet (idk I like this idea for some odd reason)

2- Bf x Pico x Gf (my mind came up with an instant idea when I saw this)

3- Error Sans x Core Frisk (idk.... i looked at pictures of these two characters as i didnt know who they were and my mind went kaboom)

Tell me of any other ideas and it may come on here. I realy, realy dont care what you say, I just want to experiment