Single developer's perspective

Dear community! I am looking for development tools and practices crafted for a single developer. Although I have a detailed concept and a long list of suggestions on how to build something new, this is not a good idea to build from scratch if so many big players have almost all of the required elements.

So I am interested in current approaches in the GitHub portfolio: how to work effectively with projects, issues, and repositories with the single developer’s point of view?

If there is nothing applicable, I am going to send a kind of RFC, so if you know about any open issues in this area, please give me a link.

Maybe an example (although partial) from history will be helpful: Bazaar had Solo mode.

If someone will be reading this thread for any reason, e.g. for its own inspiration, I have found a next great example of an integrated solution for a single developer’s experience: Fossil.