I have recieved a few over the years, just a small percentage though of what I have ordered.
This is what I remember getting:
free Hanes Beefy tee; gray
ABC 360 tee
Rolling Stone tee
GM card tee
"my sexiest mistake" tee from Oxygen; it was way too small so I donated it to Goodwill
Another time, before I had internet; I sent in an offer for a free cat toy from Iams; it was such a nice toy, and my cat loved it so much, I wrote and thanked them for it, not expecting anything other than maybe some coupons; well, I got some coupons; and they also sent me tshirt!