Alright, I failed to include a picture of the excellent Power Rangers GG game, so I’m starting with that:
Ecco the Dolphin also had both titles ported to (also made for?) Game Gear, and they hold up fairly well, and capture the feel of the console versions. My partner actually played through these rather than the Genesis versions as a kid, and aside from the trauma of the air bar looming over her had a good time with them.
X-Men for the Game Gear is one of those great examples of something made for a different system with the same title that only bears a vague resemblance. I know I played it a ton as a kid, so my perspective is skewed, but I’d say the GG entries are better than the first Genesis one (the second one utterly crushes the rest, though).
And to cap off what has quickly become a GG appreciation post, Aladdin. Similar to how the SNES and Genesis versions are completely different, this one is its own thing as well. Those ones are fun platformers, but this one is a combination of auto-scrollers and Prince of Persia-like segments. Certainly worth checking out just to see the weird genres mashed together.