Good question. I think that identifying players in the 4 mystery card sets without cards in ATG would be a good place to focus for future individual card adds. Another missing Astro is Roger Metzger...
Metzger and Tino were both in previous votes, they just didn't get enough. Ray Durham, Ernie Shore, Taylor Douthit, Cliff Melton, Dick Hughes, Greg Gagne, Pat Hentgen, Wilson Alvarez, Alex Hernandez..........