Fossify Gallery on the official F-Droid repo
The removal isn’t directly related to the buyout/fork. Simple Gallery was taken off of F-Droid due to a dependency on the nonfree Google VR being discovered by IzzySoft¹ ². Fossify’s fork has removed the dependent features to be compliant³.
Yeah I know that’s allowed under the GPL, but you mentioned them “choosing to keep a FOSS version”, which if they didn’t do that would mean relicensing. It’s still FOSS here.