If you are interested in antiques or classic furniture and art, you need to check out Vogt Auction. In business since 1975, Vogt is a favorite place to find those unique items. Tuesday is auction day, and you can preview the stock for sale from 11a to 7p. The selling starts at 7p.
You might also want to check out The Cottage Antiques on Sunset or Bygones on Broadway (on Broadway near the San Antonio Zoo.