There honestly are, imo, great games on the HuCards like Neutopia 1 & 2, Dungeon Explorer if you are into rpg style games.
Mass amounts of shooters like Blazing Lazers, Super Star soldier.
Even some good platformers like the Bonk series. Oh and I know Double Dungeons gets pooped on a bit but I beat that game back in the day and I rather enjoyed it. Although it is a bit bleak with the sameness over and over.
CD wise, yes it does show off a bit more of the systems potential with but that is because the cd games have access to more ram if I am not mistaken. It has games for most all genre's it just has more for certain ones is all so it all comes down to taste. Highly under rated system... The entire thing is just a hidden gem for those that never experienced it.
Oh.... and welcome