Particuarly in the late 1980s and early 1990's as the hobby was booming, there were several card-related publications that included insert cards. Allan Kaye's, Ballstreet, Investor's Journal, Pocket Pages, RBI, Sports Report, Sports Educational, and many more.
Most, if not all, of these publications contain cards as part of the distribution with players featured with full team names/logos. Flipping through, I don't see any specific mention of a license (MLB or MLBPA), so my question is, how were these publications able to produce and distribute cards legally? How are they differentiated from the broder/unlicensed cards?
My guess is that many of these were issued in full sheet inserts or panels as part of a magazine, which maybe is a loophole in "card" production and sale. Would be interested to know if others have thoughts because it was a prominent practice back then, but also something not seen (at least commonly) in the last 25+ years.