I have thousands and thousands of duplicate skeds available, mostly from 1970s to present:
Many are college (from almost any sport you can imagine, men's and women's, although there are a few sports that are getting a bit depleted at this point)
Football, hockey, swimming, wrestling, soccer, lacrosse, baseball, basketball, volleyball, tennis, golf, cross country/track - and more!
Plenty of pros/minors as well
Especially MLB, NFL, NHL, minor baseball, recent minor hockey
OBC'ers, if you've got a sport or team(s) that you collect, just let me know and I'll see how I can help. Or if you just like a sport or team or whatever and think you'd like to dip your toe in sked collecting, let me know that too. Tons available!
Lists of skeds that exist for most major sports/leagues; each league has a different Google Doc that you can click on to read.
Includes a home page overview.
Similar lists from previous years (typically back to 2008 or so) are also available.
Skednet has 300+ sked-collecting members.
"The Skedder News" is a hobby newsletter that comes out 6 times per year (PDF or paper versions available), with lists, articles about new (and sometimes old) skeds, classified ads, etc. If interested, let me know and I can send you the contact info for the publisher.