Kujira aims to be the next step in DEFI's evolution. In fact, they claim on their website that they are "DEFI adults". They started their project, initially relying on the Terra blockchain, until the recent collapse and halt of the chain.

Subspace, after successfully passing the first stage of their testnet, decided to launch the second stage, namely the Gemini Incentivized Testnet. What we do, of course, we launch the node. The developers said that there would be enough time for the installation for everyone, but it’s still worth it to hurry up. There are no details on the rewards yet, just put a node and hope not for caps

Celestia is a modular consensus and data network designed to make it easy for anyone to deploy their own blockchain with minimal overhead. Celestia is a minimal blockchain that only orders and publishes transactions, but does not execute them. By separating the layers of consensus and application execution, Celestia modulates the blockchain technology stack and opens up new possibilities for decentralized application developers.

The testnet consists of 4 stages and will last approximately 8 weeks.

According to the roadmap, QuickSilver is starting INCENTIVIZED TESTNET, end of May - beginning of June. What you can do is install a node and run a validator, upload data about your active validator to their Discord, and you will be given the role of Rhapsody Testnet QCKers, more details about the testnet are described in their #rhapsody-fag thread. I also saw the roles of Meme / Content creators on Discord, you can work hard and come up with something, send the work to the #language-resources branch.