We have our own marketplace in development! https://marketplace.tranquilitycity.one/#/ You can view your NFTs on the marketplace and also list them for either LUMENs or ONEs.
Attributes can also be filtered so you can search based on rarities for example!
The marketplace takes 3% of every sell. Of this 3%, 75% will be used to buyback LUMEN and add it to liquidity and also send it to game contracts. The remaining 25% will be used for devs, marketing and community giveaways.