When the Leafs dealt away Alexei Ponikarovksy for Luca Caputi, and gave Caputi a regular spot in the lineup, they kept alive a link to a couple of nearly 20 year old trades.
These two trades are the oldest made that the Leafs still have something to show from (correct me if I am wrong). They were pulled off in the early 1990's, with the Leafs acquiring a couple of components in the '92 Gilmour mega-deal. I'll label these trades A and B.
(A) November 17, 1990
Scott Pearson, 2nd rd draft pick ('91), and 2nd rd draft pick ('92)
to Quebec Nordiques for
Aaron Broten, Lucien DeBlois, and Michel Petit
(B) September 19, 1991
Vincent Damphousse, Luke Richardson, and Peter Ing
to Edmonton Oilers for
Grant Fuhr, Glenn Anderson, and Craig Berube
Now, for the trades that descended from there.
#1. January 2, 1992
Gary Leeman, Alexander Godnyuk, Jeff Reese, Michel Petit (A), and Craig Berube (B)
to Calgary Flames for
Doug Gilmour, Jamie Macoun, Rick Wamsley, Ric Nattress, and Kent Manderville
#2. March 24, 1998
to Detroit Red Wings for
Tampa Bay's 4th rd draft pick (1998: Alexei Ponikarovsky)
#3. March 2, 2010
to Pittsburgh Penguins for
Luca Caputi and Martin Skoula
Of couse, Skoula only lasted a day on the Leafs' roster before he was used to bring in another young player that the Leafs currently hold rights to.
#4. March 3, 2010
to New Jersey Devils for
NJD 5th rd draft pick (2010: Sam Carrick)