They're Called "Trios"

This card was inserted into packs of 1971-72 Topps basketball cards:

Note how Dave Cowens has his jersey on backwards. That was no goof on his part; Topps wasn't allowed to show the teams' names and could only use city names to refer to the teams. That's why Bob Love was allowed to keep his own jersey on straight.

ABA players are given an "A" suffix to their card numbers to keep them separated:

I'm going to guess that Rick Barry's picture was conveniently cropped.

These panels were stickers placed on a blank-backed piece of white cardboard. There are 26 different panels (including three with a variety of ABA team logos and one featuring NBA team logos), and there were varying levels of scarcity among the panels due to the layout of the print sheet, making for single, double and quadruple prints.

Of course, stickers that have been peeled from their backing are considered damaged and virtually worthless.