I think you will see early collectors referring to the T206 set as the "521" set. Not as you may think because there were 521 known subjects at the time, just because that is how it was initially catalogued by Burdick. You can see that moniker in some of the Card Collector's Bulletins that Leon occasionally posts. Before then, not sure it had a name. It was thusly described in 1937 as white border tobacco cards, with some of the same images as early caramel cards, and with several hundred examples known.
See, e.g., here:
http://www.net54baseball.com/showthr...light=bulletin