Dropil (DROP) is an Ethereum token and works as a utility token for the Dropil platform. No more Dropil tokens will ever be created, which is supposed to prevent further deflation. You can buy Dropil (DROP) for cryptos (for example, BTC or ETH) with some exchange platforms.
Qtum (QTUM) is an opensource blockchain platform launched by the Singapore-based team of developers in 2017. The project provides an opportunity to maintain the connection between the virtual machines and the blockchain. Also, Qtum users can create smart contracts and build DApps with the help of the platform. It is important to mention that Qtum is compatible with DApps built on other blockchains.
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.