File browser panel
Depending on how you use gedit, you may find it helpful to use the File Browser panel plugin. This plugin embeds a file browser in the side panel, giving you easy access to your frequently-used files.
You can enable the side panel by selecting gedit ▸ Preferences ▸ Plugins ▸ File Browser Panel.
Opening files from the side panel
To open files from the side panel, first open the side panel by selecting View ▸ Side Panel (or just press F9), and then choose File Browser from the dropdown at the top of the panel.
This will activate the File Browser mode of the side panel. You can then use the navigation buttons at the top of the panel to locate and open your desired files.