KDevelop is a cross-platform IDE. It supports various programming languages such as C, C++, Python, PHP, Java, SQL, Ruby, QML, JavaScript, Go, and document formats XML, HTML, CSS, build systems QMake, CMake, and version control, GUI builders, debugging and documentation tools. It's based on KDevPlatform and the KDE and Qt libraries.
Tke is a full-featured and Tcl/Tk-based source code editor. It supports syntax highlighting and auto-indentation for multiple languages. There's support for a Vim mode, code snippet and clipboard management, bookmarks and multiple cursors. Tke provides a tabbed interface with a file system sidebar. It's also NFS and lock aware, extensible per plugins, allows regex searching/replacing, has configurable menus, and allows unlimited undo/redo levels.
Suplemon is a modern, slick and intuitive console text editor with multi cursor support. Suplemon replicates Sublime Text style functionality in the terminal with the ease of use of Nano.
KKEdit is a programmers editor using the Gtk toolkit in the style of Mac BBEdit. It's not an IDE, but provides slightly more coding functionality than other text editors; syntax highlighting, function outlines/jumping, external tool and binding and an inline-shell, remote editing, manual viewing, and remembers editing sessions. KKEdit uses non-flat tabs and icons per default.