I think a complete "master" set would be one of every card for that particular set including base, parallels, inserts, insert parallels, autos, etc. I guess there could also be a "master" base set that would include just base, Sps (if any) and base variations (photo variation for example) not including parallels like cognac, hope, etc.
Collecting Phillies base cards from 1950-present
Collecting all catcher prospect and rookie cards
Collecting all catcher prospect and rookie cards