Looking for another smaller species

[Ouroboros]

So I just recently got my two Animal Plastic T3s for my adult Ball Python and my subadult BRB, and they are just the best. My corn snake is getting bigger every day and she'll eventually have a T3 as well (3'x2'x1') stacked atop the other two, and then I want to get a fourth T3 with the divider to make two 1.5'x2'x1' enclosures, one for when my Kenyan Sand Boa grows up, and another for WHO KNOWS WHAT.

I've looked into Rosy Boas and Rubber Boas and Hognoses, but was just wondering if there were any other species that would be comfortably housed in a 1.5x2x1 enclosure. Maybe a male Mexican Black Kingsnake?

Point me in a direction!