Eg: lazygit https://github.com/jesseduffield/lazygit?tab=readme-ov-file#... https://github.com/sxyazi/yazi https://github.com/darrenburns/posting or I guess Vim would be a prominent example.

Peoples definitions will be on a gradient, but its somewhere between CLI (type into a terminal to use) and GUI (use your mouse in a windowing system), TUI runs in your terminal like a CLI but probably supports "graphical widgets" like buttons, bars, hotkeys, panes, etc.