Apps with 'Word completion' feature

Vim ("Vi IMproved") is an advanced text editor that allows syntax highlighting, word completion and has a huge amount of contributed content. It also has a GUI version called GVim.

Official text editor of the GNOME desktop environment. Has syntax highlighting and is suitable for programming, with support for several languages. It is extensible with plugins.

Wikidata is a free and open knowledge base that can be read and edited by both humans and machines.

Word completion tool reducing keystrokes with customizable dictionaries, user-added terms, system tray access, F1-F10 selection, and bilingual support.