Brush - Aedif/multi-token-edit GitHub Wiki
A brush tool can be activated by clicking the brush icon in the header of Mass Edit forms
Once selected your cursor will be transformed into a brush allowing you click and drag over placeables on the canvas to apply fields selected in the form onto them.
https://user-images.githubusercontent.com/7693704/211565859-0cc6105d-f023-4f84-9b85-5593475e5bc0.mp4
The brush can also be accessed via the Presets browser window.