Alternatives to TeXShop
Native macOS LaTeX editor bundled with MacTeX. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
TeXShop
Native macOS LaTeX editor bundled with MacTeX.
Replacements
Listings that take over the same core job as TeXShop.
TeXstudio
Full-featured LaTeX editor with completion and inline preview.
TeXstudio runs on Windows, macOS and Linux with completion, inline preview and table assistants, but it needs a separate TeX distribution and has a denser interface.
Kile
KDE LaTeX editor with a structured project view.
Kile is a free KDE LaTeX editor with a project view for multi-file documents, available on Windows and Linux but not on macOS.
Similar software
Related functionality, not a direct replacement.
GNU Emacs
An editor that is really a Lisp environment, extensible to the point where people run their email, calendar and shell inside it.
Visual Studio Code
Microsoft's code editor, free to use but shipped under a Microsoft licence rather than an open one.
Vim
The editor that is already on every server, with a graphical build for Windows and a licence that asks you to donate to Ugandan children.
Sublime Text
A fast native editor for code and prose, paid for but with an evaluation that never stops working.
BBEdit
A long-running macOS text and code editor for writers, web authors and software developers.