
My favorite is a Western Hognose Snake (https://en.wikipedia.org/wiki/Western_hognose_snake) because they are very small, very docile as a pet, put on a bluff show, and are intelligent and curious enough to act like a toddler (mine anyway). I have had one for a year and it is less than a foot long. It started out too small to eat a whole pinkie mouse, so I fed it parts of one. Now I feed it pieces of rat tail (a very unusual thing to feed anything) and very occasionally a pinky mouse. If you can imagine a snake being cute, then that is what western hognose snakes are.
I also have a HUGE (about as long as your mother is tall, and about as fat as your wrist) Bullsnake (https://en.wikipedia.org/wiki/Bullsnake) that is a nonvenomous rattlesnake mimic. It gets angry, hisses very loudly, curls back, vibrates its tail against the ground or anything else, and strikes at you (with a closed mouth, its all bluff). It is VERY impressive in its attempt to get you to just leave it alone, and is probably what most gets killed by people who think they are seeing a rattlesnake, when it is actually harmless. It is so impressive that it even scares me and I am not afraid of snakes and _know_ it cannot hurt me!

But my two snakes are like polar opposites in their behavior, even though they both generally have the same pattern. The Western Hognose Snake is much more docile, so it is my favorite reptile.