South American puffers (max 3") are better in group of 4-5 or more with 15g each. They have a problem with overgrown teeth. If they are not kept in a group, then they will start acting funny and unnatural. Nippy and not community safe in the long-run.
Then there are the Avocado puffers (max 3-4"): aggressive and should only be kept alone in 20g min. They also have problems with overgrown teeth. My previous avocado puffer is with my brother. I'll trim in a few months.
Congo puffers are amazing fish, but are not very active. I love the way my former congo buried and changed colors.
The rest of the FW
puffer fishes are either lurkers or nocturnal, so you won't see much activity from them.
Both SAPs and Avocado do not look like the typical round puffer. SAPs are more slender and Avocados are flat (a little bit thicker than silver dollars). Both are able to get a round tummy like a typical puffers, but must have teeth trimmed least twice per year. I think it stops people from keeping them. Plus, the Avocado need a solitary tank and the SAPs need too big of a tank. IMHO
I like both of them.
Feeding my Avocado (A. Modestus) Puffer - YouTube
Last option is a Fahaka puffer. They get massively big at 18", so tanks with 24" wide and 120+ gallons is required. My guy buries like a congo puffer, active like the SAPs and Avocado, and do not have problems with teeth if given snails and hard-shell crustaceans. Also must be a solitary fish.
Dwarf puffers are too small IMO
Figure 8 is a great fish because the chicks dig the roundness of their natural appearance. Active like the SAPs and Avocado, and does not have problems with teeth if given snails and hard-shell crustaceans every once in a while. You need a little bit of marine salt though.