I love these and have a couple, two Football ones as well. I still need at least one baseball variant. A&BC did some in the UK and Dan Dischley nicked some of the graphics for TTS starting in 1972.
They seem to have been inserted in wax packs but given how scarce they are, I can't believe they were in many packs, and no one really seems to really opening a pack and seeing these.
I suspect more are out there, especially given the catcher Dischley used along with the pitcher who appears on one of the known inserts.
I've blogged these:
https://www.thetoppsarchives.com/search?q=waxy