I've been watching Grug Notes -- grugnotes.com -- for quite a while, and it has made impressive progress. I think it deserves mention here. Its basic format is a nice web-based outliner with level-based coloring. But then it has sophisticated integration that can work with outlines intelligently via chat, including things like indenting and outdenting.

(Sorry for the type: should read "sophisticated AI integration".)

@Lucas, have you tried the app?

@Paul, yes, I've tried it periodically over the last year, although I've never used it heavily. When I tried it recently, I was impressed by how well-integrated (and fast) the AI aspect has become. It's an interesting example of how LLMs can be made to be "hierarchy-aware." I use InfoQube as my main tool for idea processing, but I will probably experiment more with Grug Notes for moments when I want to quickly get some AI nudges while outlining.