1. Green Tree Pythons
2. Carpet Pythons (mainly IJs and IJ Jags)
3. White Lipped Pythons

I feel like I'm forgetting one that I really like but that's just not coming to mind. Regardless, I love arboreal snakes so GTPs get the top vote. (Some day I will have some, for now I'm focussing on ETBs.) Irian Jaya Carpet Pythons are amazing. They're more docile than some other carpets, they're trash cans for the most part, don't get huge, are quite hardy, etc. To me one of the best starter snakes out there! And White Lipped Pythons are simply gourgeous. I can't get over their colouration and over all look, simply stunning. I've never worked with them, but maybe some day.