Unity's intuitive drag and drop system makes it easy to forget how boring and time consuming dragging and dropping really is. Therefore I am proud to say that i am very familiar with writing Unity editor scripts for any purpose. My most used script to this date is the simple Faster Faster script, saving debugging time when waiting for that-specific-error™ to occur.
I've created two map editors one creating planets for a low poly racing game, saving them as text files with regions written as short base64 lines, to fit with use for git version control. The other a Tile map editor creating wall-meshes on the fly, allowing me to send complete maps as JSON files, generating them runtime rather than saving scenes and having to update the entire app just to add a single scene.
For Machineers I among many other things created a button that in one click would finalize all references after setting up elements for a puzzle. And a full dialogue editor capable of triggering game events, loading new levels and saving states to the users savegame. This allowed our game designers to create the entire dialogue flow for Machineers, without needing to modify the xml.