1) I know that HackerNews has a strong anti-crypto bias, but let me pitch Hub20 (
https://hub20.io), the self-hosted payment gateway for ethereum (and EVM-compatible) blockchains I'm working on is usable - if you are willing to invest some time/energy to overcome the rough edges - but I am having more ideas than capacity to build all I have in mind. Integration with more layer-2 projects (it started with a focus on Raiden, now it can also work with Optimism/Arbitrum, this year I want to integrate Loopring and zkSync) to make transactions cheaper/faster.
2) Not crypto related, but still about decentralized web: If someone has experience or interest in working with search and content discovery on the Fediverse, I'm willing to collaborate and even (modestly) sponsor whoever wants to work on a "CommonCrawl" for fediverse content, and further on a "CommonIndex" and "CommonRank" system that can make it easier for instance administrators to offer a global search system that avoids replicating indices of the entire fediverse on each instance.
3) I started learning Go a couple of times, but I haven't found a project that is small enough for me to take on individually but big enough to make it interesting to continue. I have two ideas that if might appeal a more experienced Go developer that could at least provide some mentorship/guidance:
3.1) adding an extension to IPFS that gives adds a "Web Of Trust" to nodes and use that as a way to build an ACL-based permission to my pinned content. Use-case: if you have content that you don´t mind being public but you don't want to have your server as the main distribution channel.
3.2) Adding some kind of middleware for syncthing that allows pre/post-processing of files before syncing. I've written some of the motivation about at https://raphael.lullis.net/thinking-heads-are-not-in-the-clo..., but another example use-case I'd be interested: I host my music collection (large FLAC files, hundreds of GBs) on my NAS, and I'd like my phone only with a subset of these songs, converted to some reasonable lossy format).