Javascript is the easiest way to get going, and there are lots of web clients out there (particularly in svelte). I've got lots of issues open at https://github.com/coracle-social/coracle/issues if you want to contribute to Coracle. Otherwise, you can find a list of projects here: https://github.com/aljazceru/awesome-nostr

One way you might consider contributing is by building data vending machines, in particular I'd be interested in one for search.