I tried searching for something that had all the web3 RPC endpoints in one place so I can test/play with whatever on my local node. Postman is an application that you can use to easily test APIs and modified requests in a easy-to-use GUI. So, I've decided to import everything from the wiki and share it in a public collection - https://getpostman.com. It also comes with documentation - all credit to the people who wrote the wiki as I copy/pasted it - where you can see the request (change the language in the top right) and the notes on the request in 2 side-by-side panes.