During my time as a Unity developer, I programmed some editor tools to make certain tasks in the editor a bit easier for designers and other developers.
Legacy 2 PBR - When Unity introduced their Physically-Based Rendering system (PBR), a lot of teams wanted to update their shaders to work with the new system. My tool did this automatically! Users could drop their shaders into a custom editor window and automatically see the nearest built-in PBR equivalent. (If they didn’t like that, they could also select an output shader themselves.) With the click of a button, new shaders would be created based on their mapping. This tool was for sale on the Unity Asset Store.
Easy Layers - This was a nifty tool that gave users quick and easy scripting access to Unity’s physical layer masking systems. This tool was for sale on the Unity Asset Store.
Random Obstacle Generator - I made a proprietary tool for the Yeti’s Quest project that allowed our level designer to adjust the random obstacle generation values along the player’s running path. It saved a ton of time and relieved the burden of editing code files directly.