There is a really curious subset of these, games for old hardware that are not being released on that hardware.
Namco has really good modern ports of Gaplus and Pac-Man: Championship Edition for NES for some of their game collections. M2 did a Sega Tetris port for Sega Genesis which they put on the Sega Genesis Mini.
I think maybe the Fantasy Zone II: The Tears of Opa-Opa up-port to System 16 released on PS2 might have been the first of these.
GG Aleste 3: Last Messiah for Game Gear released as part of the Aleste Collection and on the included Game Gear Micro in the special edition, is an interesting recent example.
Now that I think about it, I guess all of these so far seem to be coming from M2 and Namco, unless I’m overlooking some.