Samuel Bernou writes:
This free addon add the classic 'Ctrl+T' quad-corner transform feature of 2D software to Grease pencil.
Originally I wrote a right-click select proposal to ask for this as a dedicated active tool read here and upvote if you like the idea). Then I wanted to make a prototype with a lattice hack. Turns out it worked pretty well, so I pushed the UX a bit further to have something usable while we wait for an integrated solution.
Download link on Box deform Github repository
Here is a detailed demo of the tool:
