Nor cards picturing him with the Tigers, Reds, Yankees, White Sox, Padres, Red Sox, or Dodgers. He will only sign Blue Jays cards for some reason.
He spent time with all of those other teams during his 21 year MLB career (and I'm making the assumption that cards were produced picturing him with all of them), but he has some variety of long-standing policy against signing baseball cards that picture him with any team besides the Blue Jays. I have seen a few scattered autographed cards of him with the Tigers, Yankees, and Padres; apparently if you catch him in the right mood, he is willing to break his own rule, but 99% of the time it's Blue Jays cards only. And this actually holds true for his paid signings as well. The man will turn down money from fans just because he only wants to sign Blue Jays cards.
Now, I know that Boomer seems like an interesting character, and that sure comes through on his TV appearances, but I have never heard a reason behind why he only signs Jays cards. Between his various TV appearances, a number of charity golf outings, and a paid signing here or there, he is accessible enough, but until he lifts this embargo, I'm stuck with having this signed Blue Jays card in my collection. Hopefully one day I will track down a signed copy of any one of his Orioles issues: 1996 Flair, Fleer Update, Ultra, Upper Deck Update, 1997 Fleer, Score, Topps.
But here's the strangest part of this whole deal to me; David will sign 8x10's that picture him as an Oriole.