Yeah I'm pushing it a bit to say that Dave May was "missing" from the 1979 set, but I came across this photo of him as a Pittsburgh Pirate, even though he only appeared in 5 games for them at the end of the 1978 season, the last five games of his career, so I just had to create a card.
Take a look:
May appeared solely as a pinch-hitter for the Bucs in '78, thus closing out a decent 12-year career that saw him play for the Orioles, Brewers, Braves, Rangers and Pirates.
I profiled his career more in-depth a little while back when I created his "missing" 1977 card, a card that SHOULD have been produced by Topps.
You can take a look at that post to read further (or simply go to Baseball-Reference.com).
Cards like this one are definitely fun to do, even IF they really had no business being in a Topps set.