Stafford was only man to command an Apollo spacecraft twice - Apollo 10 and ASTP. He also previously flew with Wally Schirra on Gemini 6 and commanded Gemini 9.
He was also the last living crew member of Apollo 10.
The list of still living astronauts who flew an Apollo spacecraft:
Jim Lovell, CMP 8, CDR 13
Bill Anders, LMP 8
Dave Scott*, CMP 9, CDR 15
Rusty Schweickart, LMP 9
Buzz Aldrin*, LMP 11
Fred Haise, LMP 13
Charlie Duke*, LMP 16
Harrison Schmitt*, LMP 17
Joseph Kerwin, Science Pilot, Skylab 2
Jack Lousma, Pilot, Skylab 3
Edward Gibson, Science Pilot, Skylab 4
Vance Brand, CMP ASTP
* - walked on the moon
We are also down to three Gemini astronauts - Lovell, Scott, and Aldrin. Gemini 12 is the only pre-shuttle mission with all crew still living.
Godspeed, Tom Stafford.