The colorization process is often difficult and non-trivial, so it's hard to imagine why anyone would proceed with some of these. Yoshi and Yoshi's Cookie both have NES ports. (Also, Yoshi isn't really very good.) Castlevania II famously got a GBC release in Konami GB Collection Vol. 3. I guess GB Street Fighter II has a few unique things to offer, but did anyone really like that one..?
Final Fantasy Legend might be best enjoyed in its Wonderswan Color port; the DS remakes of the other two games might arguably be a little too different. Runes of Virtue II had a SNES version.
Final Fantasy Legend 1/2/2
Ultima: Ruins of Virtune I &II
Final Fantasy Legend might be best enjoyed in its Wonderswan Color port; the DS remakes of the other two games might arguably be a little too different. Runes of Virtue II had a SNES version.