I know Ron Kittle spent some time in Glens Falls with the White Sox AA affiliate. John Smoltz came to town very briefly as a single A Detroit Tiger. I'm sure there were others, but those to come to mind.
Coincidentally, Dave LaPoint graduated from Glens Falls High School and went on to have a decent career, winning a World Series with the Cardinals and playing for the Yankees and other teams. He ended up starting a non-MLB-affiliated league in the northeast and it stuck around for a handful of years and owned a team that played in the same field (East Field - named as such because it was in the "East End," of Glens Falls (where my dad grew up). The quality of baseball was less than that of single A, but it was still fun to watch.
East Field is now used for (I believe) a JuCo league. The field has gone to hell, unfortunately. Sad to see it deteriorate.