Supposedly, you’ve seen “the list”. Tell me where it is if it isn’t on gun-talk blog from somebody..
There probably is a list out there but it is more likely you learn by just using and knowing about guns.
I did do one search and the first line that came up on Mec-Gar’s site says that if you own more than one gun you more than likely already use Mec-Gar magazines.
It is common knowledge among gun users that Mec-Gar makes nearly all original equipment mags.