Bright Futures Farm helps all horses, though they have helped a large number of OTTBs.
They are having an auction to raise money for an automatic feeder for one of their senior equines who needs to be feed many small meals multiple times a day.
Items include a hind shoe worn by Brethren in his Sam F. Davis S(G3) win, a Stay Thirsty shoe, 2 shoes from Dreaming of Julia, and prints of: Affirmed, Barbaro, Citation, Count Fleet, Ferdinand and Exceller(on one), Gallant Fox, John Henry, Omaha, Ruffian, Seattle Slew, Secretariat, Sir Barton, War Admiral, Whirlaway, and the Kentucky Derby winning fillies(on one).
Plus other random items. Reserves are posted on each items page.
Edited to add:
They must still be adding items. There are also 4 shoes worn by Palace Malice with COAs.