Love this list! Here's one idea I had for an atproto app:
One of my favorite things I've found on some personal websites is the /uses page of things you use (code editor, terminal, browser, computer, monitor, etc.) An example off the top of my head would be https://natalie.sh/uses. An atproto app would be nice for this because you could set a category and see a list of the stuff all the people you follow use for it, and not just one person.

Thank you! This was more of a shower-thought-turned-blog-post so I'm glad it resonated!