I cant seem to find any info on this. I have seen a WIDE array of flashlights on rails from pictures. Any help would be appreciated
All of the above:
M951 seems most prolific.
But I've also seen M96's, as well as Insight M3X's, M600A Scout Lights, M900 VFG Lights, Pentagon Lights, and mounting hardware for a variety of handheld flashlights.
Not to mention the old Surefire Classic series lights. You would hardly be wrong if you mounted one of those on a "clone." Otherwise, if you're just wanting to know what's considered suitable for the military, those are most of the ones I've seen issued.