1. Donate it. Some charities that accept wedding dresses are Angel Gown and Brides for a Cause. Do a quick Google search to see what non-profit organizations in your area accept wedding gowns and bridesmaid dresses. Local theater companies also accept gently worn dresses.
2. Sell it. Sites like Tradesy make it super-easy to sell bridal gowns, bridesmaid dresses, and even wedding décor. Sabrina's in Ardmore is a popular store that accepts bridal gowns that originally retailed for $1,000 or more. You most likely won't get what you paid for the dress, but can still earn some money back.
3. Put it on display, as seen below. OK, you can really only do this if you have the space. And yes, that is Adrienne Maloof from the Real Housewives pictured below. Maybe I can do this in my next house! If you don't live in a mansion like Ms. Maloof, you can cut up a piece of your dress and display it in a shadow box. You can also do this for your veil, gloves, or an accessory that you wore.