What tools do you use to manage projects as a solo dev?

So... by "manage projects" you mean all the metadata related to tasks, bugs, todos, features, deadlines and milestones? (I've heard some people use "manage projects" to mean "how do I build the source? make? cmake? etc.")

To be honest, I just save all that stuff in text files in the same repo as the code (though usually in a specific directory at the root of the project.) I have some tools that pull meta-data out of text files so I can query them for things like "give me a list of open items" or "give me a list of items tagged with a specific release target."

It takes some getting used to if you like HTML interfaces, but I grew up on the command line so it works for me.

Mostly paper kanban boards. From time to time I tear down the old one and make a new one. I broke mine down into two sheets in order of long-term vs short-term speculativeness then wrote some overflow ideas onto a third sheet.

Paper is my ‘killer app’ when I am having any difficulty with a project. The last thing I need is another window on my virtual desktops to navigate to, if I want to knock down tasks like a beast I print them down and cross them out.

Everything is in Notion for me.

File explorer. I put them in separate folders so their files aren't all jumbled together /s

Can you clarify what you mean by "manage projects"? If you mean issue tracking / notes, I sometimes use github issues, but most often I simply use a markdown file in the gitignored directory where I keep assets that shouldn't be checked in (psds, db backups, and so on). The mermaid extension for vscode makes it easy to throw together flowcharts in that same file. Sometimes I use google tasks for checklists, since my other todo's are in there too.