I built + maintain todolist[1] which is a GTD-style task management app for the command line. It's getting a bit of traction now which is pretty fun. It got a ton of upvotes on Product Hunt which was really cool to see[2].
I have very loose plans to monetize via a paid subscription for syncing with other devices / phones, but there will always bee a free / open source version as well.
[1]: http://todolist.site