This is a camera module to replicate the type of 2D camera you would find in classic isometric CRPGs like Baldur's Gate / Icewind Dale, Planescape Torment, and Fallout.
It allows for a variety of movement options over a large 2D background, including mouse-wheel zooming, screen-edge scrolling, and click-and-drag movement with the middle-mouse button.
Area map background is courtesy of user Aranthor of the Gibberlings3.
If you just want to test the camera functionality, download a build under Releases. Hit ESC or click on the rug at the South end of the map to exit the game.
This is built for Godot C# 4.1+, although you could easily adapt it for 3.5 Mono if you update the references to the MouseButton enum in the Camera.cs _UnhandledInput method. These references were renamed and overhauled in v4.0.