JetBrains Fleet is described as 'Built from scratch, based on 20 years of experience developing IDEs. Fleet uses the IntelliJ code-processing engine, with a distributed IDE architecture and a reimagined UI' and is a Text Editor in the development category. There are more than 100 alternatives to JetBrains Fleet for a variety of platforms, including Mac, Windows, Linux, BSD and Haiku. The best alternative is Visual Studio Code, which is free. Other great apps like JetBrains Fleet are Notepad++, Atom, Sublime Text and Vim.
JetBrains Fleet is mainly a Text Editor but alternatives to it may also be Code Editors or IDEs. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of JetBrains Fleet.
4coder is a minimalist, cross platform, programmable, code editing environment, catering to the needs of low level programmers. It allows you to use one work flow across Windows, Linux, and Mac (with the exception of your debugger... for now.).
vy is a modal editor with a very modular architecture. vy is built on top of Tkinter which is one of the most productive graphical toolkits; It permits vy to have such a great programming interface for plugins.
Tilde is a text editor for the console/terminal, which provides an intuitive interface for people accustomed to GUI environments such as Gnome, KDE and Windows. Example: copy current selection is Control-C; paste previously copied text is Control-V.