Turtles, short answer - too much trouble and space.
Hard shell turtles mostly take a lot of time and a 4', 55 gal would be a min. for that.
There is a soft shell turtle, males and females (usually larger) can be different sizes as adults, you can look them up, I don't believe they come out of the water (as in hang out on dry land) but they can bask and sorta burrow/root around in mud/sand, eat fish like a planted area, it's difficult to replicate their natural habitat.
So Chameleon, my favorite, but again has special needs, (likes a more calm environment to live in), humidity, lighting as do most creatures we remove from their natural habitat to live in our houses.
Bearded dragon I have not had but understand is a good starter, get pretty big.
Thoroughly check all aspects of what the critter needs, buying or adopting is the easy part, its everything you have to do after that, that it starts getting complicated!!