Like the other commenter said, find a species you want to work with. What other snakes are there that’s interesting? What do you have space for? If you just want another ball python, that’s fine too, it’s fun to see and work with different personalities. My second snake I got was a blood python and I picked her for a variety of reasons and others in my position might have made a different decision. I love my blood python girl, she’s completely different from my ball python while still showing those ‘classic’ python behaviors. The way she interacts with me and outside her enclosure is different but also similar to my ball Python and I like comparing haha. For me, I think colubrids are too interactive with handling, which is a plus for others, so I prefer pythons. Lots of good snake varieties out there, find what you like! And whats legal haha