We just released a secondary market in Scout Game. You can list a Developer Card for sale from your profile and price it in USDC. 

When a player tries to buy that Developers Card they will get the cheapest price, weather from secondary or primary. 

There is no dedicated market view. The listings are integrated directly into the main Developer Card collecting mechanics. 

https://scoutgame.xyz/

Just dropped a secondary market in Scout Game! 

You can now list Dev Cards for sale in USDC right from your profile. Buyers always get the best price, primary or secondary.

Fantasy Sports with Onchain Developers. 

Scout. Build. Win. Brought to you by the builders of SUNNYs and CharmVerse.

https://scoutgame.xyz/