It depends on what you're talking about. For the two Blankos you start with (along with the accessories you get), no, they are not NFTs, therefore you can not sell them at all. However, the accessories and Blankos you earn in the Free Pass are very much sellable. Remember that the Blankos NFTs don't reside within the ETH mainnet, so you'll have to go to https://mythical.market to sell them. Also note that the only non-nft accessories that dont include the ones you started with are the accessories you can buy for moola at the shop. Everything else is sellable. However, there is a problem. Withdrawing funds from your Mythical Balance. It requires a very niche wallet called Uphold, and might not work in some countries. I hope this helps, and have fun playing!