GUI editors are graphical based editors. It is easy and elegant to use. It ha lots of components for support of user. Various such editors are available in market.
1. Gedit :
It is default editor for GNOME based UI. It is easy to use, support for many languages.
2. Atom :
It is open source editor developed by github. Atom is powerful editor for developer. It has version control support , most of languages are supported. It has many extensions available that makes it more useable.
3. Sublime Text :
It is also a famous editor, mostly famous in web developer community. It has support for most of language,VCS. It is licensed use purpose.
You can explore suitable editor for yourself from various types of editor available in market.