If you can make a list or compile a gallery of what you have, try selling them on Facebook (but also here! Just in case!! I don't wanna miss out). eBay can help for price checking, just take into account the 10% fee to sell on there. Depends on if you're looking to maximize money or just clear out the space.
Some G3 are sought after. Any holiday ones, fair exclusives, international exclusives, birthflowers, store exclusives...there are some other ones mixed in there too, I'm sure. Unicorns and pegasi generally sell for more than the others (unless it's a core 7 one).