BLOCKv (VEE) is the utility Ethereum token of the BLOCKv platform, where users can develop virtual objects (vAtoms). You can trade VEE tokens with a number of exchanges. BLOCKv (VEE) token was launched in 2017.
Comet (CMT) cryptocurrency is formally accounted on the number of ratings.. However, there is no up-to-date official information about its current status. Therefore, we can conclude that the coin is currently inactive.
Decentraland (MANA) is currently based on cryptocurrency Ethereum protocol. You can trade this digital asset on the fair number of exchanges. For example, Binance features MANA/BTC currency pair.