Some headstamp additions to freakshow10mm's post, with quality comments based on my experience:
Fiocchi brass is stamped Fiocchi or GFL - excellent
Winchester brass is stamped Winchester or WIN or WCC - excellent
Federal brass is stamped FEDERAL or FC - excellent
Prvi Partisan (Yugoslavia) brass is stamped PPU in cyrillic letters, looks like nny - not good in pistol calibers. Wrong primer pocket size, wrong primer type, eg. 45ACP brass with small primer pockets. Good in rifle calibers, and I believe Graf's rare caliber brass comes prom Prvi Partisan
Igman Konjic (Yugoslavia) brass is stamped IK, good rifle brass. Never saw any pistol ammo from them.
Malaysian military - stamped MAL, bad news. Heavily crimped in primer, too-small flash hole makes it almost non-reloadable
Note on PMC brass: it varies greatly. PMC is just a holding company, and has been in and out of bankruptcy a few times. PMC started out as Pan-Metal Corp, then became Patton-Morgan Corp, etc. Their brass/ammo has been Korean/US/Russian in origin. Their Korean and US brass is fine.