Mine has to be Dragon Quest: Rocket Slime, a DS spin off of the Dragon Quest series that sees you playing as a slime operating a tank and rescuing the people from your town. You run around the overworld, collecting items to use as ammunition and saving money to upgrade your tank. The art and music are just as great as you’d expect from the Dragon Quest series. It made fantastic use of the DS’s dual screens. It’s also written for a younger audience, so a lot of it is just really silly and fun! Try it out for sure, I’m so sad there’s no sequel :(
All of the games in the Tribes series, my personal favorites being Tribes Ascend and Aerial Assault. Tribes had a play style similar to Halo but with a movement more like Unreal along with a touch of ‘surfing’ over land and some jetpacks. They’re all great fun and still fun for me to play today. IIRC, the last game’s official online servers are no longer active, but there is a community following for Tribes Ascend that helps keep the game alive and updated, look up TribesLauncherSharp and TAMods for more info if interested. I backed up the disc I have for Tribes Aerial Assault to an ISO and it works great in PCSX2. With 1080p/4K rendering, extra graphics options, wide-screen patches, and controller customization it’s way easier to play than originally on composite CRT with a Dualshock.
Tribes was absolutely like nothing else… And still feels innovative and exciting today. Amazing, intricate maps, nuanced team dynamics, tons of interesting equipment, vehicles, and gadgets… And of course the movement (skiing with jetpacks, and jumping with explosives) was legendary. Some of my best gaming experiences by far.