Scroll through formattings of special characters. Highlight text and hit <Alt-v>. Selectable languages, including: ascii, hex, decimal, html name, latex.
Copy or Move scrollconvert.plugin and scrollconvert.py into ~/.local/share/gedit/plugins
Then enable under Gedit: Preferences: Plugins.
Highlight special character or code and press shortcut key, <Alt-v>. The selected character or code will be replaced by the next available value. Available languages are selectable under the plugin's preferences. Ascii and Html Name are enabled by default.
NB: Some Latex codes require optional packages or encodings to be used.