I would love to see more games added. I also wouldn't expect any additional games to be rewritten for modern widescreen, they could be straight up ports. I just want something that compiles all the classic 2D side-scrolling Sonic games (not counting Mania which can continue to be its own separate release), and maybe a few of the best 2D spinoff titles.
Here's my list of what I'd love to see added as bonus games:
Sonic Advance
Sonic Advance 2
Sonic Advance 3
Sonic Pocket Adventure
Sonic (Master System)
Sonic 2 (Master System)
Sonic Chaos (Master System)
Sonic Triple Trouble (Game Gear(or if possible, an updated Master System build?))
SegaSonic The Hedgehog
Sonic Battle
Sonic Spinball (Genesis)
Sonic Labyrinth
Dr. Robotnik's Mean Bean Machine (Genesis)
Knuckles Chaotix
Tails' Skypatrol
Tails Adventure
I know there may be a few titles that one might ask, what about them? But for one reason or another I don't think they belong in this kind of collection. Games like Sonic R, Sonic the Fighters, Sonic Blast, Sonic 3D Blast, Sonic 4 Episode 1, Sonic 4 Episode 2. It may be an arbitrary rule, but I feel like any Sonic game that uses 3D models or renders of 3D models just doesn't fit with what the rest of this collection is or could be (this also helps us avoid Sonic Blast entirely which I'm sure most of us would prefer to pretend never happened to begin with). The Sonic Drift games I think should be omitted because they're just so bad outdated racers that I'm not sure why one would ever want to go back to them when games like Sonic Racing Transformed or even Sonic Team Racing are readily available today. And then the DS games might be kinda a good fit, but even if they didn't work with 3D models, I just don't feel that DS games tend to translate very well to single screen experiences.