Free resources:
ALAN13-feature-packThis project contains an abstracted part of the source of the game ALAN-13 Reformation, which meant to help other Godot developers to kickstart their own isometric grid based games. This is a Godot (mono version) project, using C#. The code was built for our own specific use case, so some of these solutions might not be suited or seem to be an overkill for your needs.
godot-localization-editorThis project is part of the ALAN13-feature-pack, which meant to help Godot developers to kickstart their Game development in C#. This particular repository however works as a standalone developer tool you can use to handle localization files for Godot projects.