from my experience water dragons are quite hard to care for, they can get a specific water dragon nematode from dirty water and they are pretty hard to keep clean if kept indoors, beardies are good but it's very expensive to keep them running (heat). Varanus acanthurus are great and easy to look after, they can become very friendly my ones always climb on me and never run under cover. Geckoes are also easy to look after. I am keeping bynoes geckos at the moment and they are very hardy and are really interesting to watch as they stalk crickets through their cage. blue tongues are good but they need a big space. Saw shelled turtles may be a good starter for you since you kept fish you would have experience with aquatic animals, they are also very friendly and not at all shy and they are very very hardy, but they are pretty messy.