Looking for the best snake species for me.

As the title says! I have reptile experience, as I have crested geckos already. I just have odd constraints that might prevent me from getting a snake. I'm a disabled adult, and my mom's stipulation is no rodents. She doesn't want them in the freezer (which is fair). And the space I have for an enclosure. I could house something like a 4x2x2 or something of similar width. Any suggestions on species then? I'm heavily considering garter snakes, but with how active they are, would a trio need more room than that?