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 :(
Allegiance
Wildly asymmetric sci-fi RTS sorta - one player per team was actually playing an RTS but everyone else on the team flew one of the actual ships, so the commander was more like making suggestions. Super fun space dogfights and sometimes you could just chill and be the turret on a bomber. One hilarious advanced strategy was to have some of your extra supply ships line up nose-to-tail with the bombers and accelerate them towards the enemy base.