Really, let's think about this. If you take my old advice from a few days ago and build something that you want, even if you're unsure if anyone else is like you in the world and you're a unique snowflake with delicate sensibilities, what software do you not currently make and use every single day and also pay for? We're trying to make a living here, after all. I don't know which software you make and use every day but if you're like me and you write software every week day for a living, and you're a little bit security conscious, here are my top 3.
I should probably stick an affiliate link in here to make some money, but I'm not because I won't make any regardless. 1password is far and away the most used app I paid for back before it was a subscription service. I paid $99 one time for this beast and I still use 1password 6 today. It definitely needs some love, and I've been thinking about making one and charging $29 one time for it, since I only use the sync over wifi function anyway, it's not that I hate the cloud, it's just that I hate the cloud.
OK, I don't pay for this, but this is the thing that I use the most. I've been using it almost every day for I don't know how many years. I've learned all of it's quirks, the inside and outside. You know you've gone too far when you're bisecting things and rebasing to keep a "clean history", because that's just how many repos I've made or been a part of, I know how the history will look with like 10 different crazy train tracks after 15 people are merging multiple branches from any point in time. Git is a crazy good tool that I mean... it's something that I would consider making a GUI for and charging $$ if there was a demand (on top of the existing million other git GUIs that are free/open source).
Atom + Proto REPL + Compliment + Ink / IntelliJ + Cursive
I've never made a text editor before, and I'm sure it's a ton of hard work... I think, but this is something I'm very interested in replacing in my current workflow. I don't have a problem with Electron so to speak, my main problem is with atom itself. VS Code seems like a nice alternative, but I'm looking for something more like LightTable, but up to date with the latest clojure changes like tools.deps and other things. The idea that functions are a natural extension of the folder/file hierarchy is something that IDEs do well at least in the side bar, but they open a whole file in a tab, because clearly we can't do better than that. I think we can, I'd like to explore this a little bit, similar to how Light Table's first version showed multiple functions side by side instead of in a file.