Visual Studio Code
https://code.visualstudio.com/

Vim
https://www.vim.org/
https://vim-jp.org/

GNU Emacs
https://www.gnu.org/software/emacs/

Geany - The Flyweight IDE
https://www.geany.org/

組み込み＆デスクトップ向けクロスプラットフォームソフトウェア開発｜Qt
https://www.qt.io/ja-jp/

The GTK Project - A free and open-source cross-platform widget toolkit
https://www.gtk.org/

gtkmm - C++ Interfaces for GTK+ and GNOME
https://www.gtkmm.org/en/

KDE Developer Platform
https://develop.kde.org/

GNOME 開発センター
https://developer.gnome.org/