I love my garter snake, such great little characters, always busy and fantastic feeders. I'm treating mine for a mouth infection ATM but even after being man handled and having iodine in her mouth she feeds. She is only the size of a pencil ATM too.
As above, dwarf boa or smaller carpet or even a male blood (or Borneo or Sumatran short tail) python if you are willing to keep humidity right, with all these tho don't buy online I'm, buy one that's chill from the word go, from someone you can actually handle it.
Bhb have nice scaleless Texas rats too.