[Tool Idea] Merging patterns using the loop function (pattern editor)

Hi all,
lately, while editing in the pattern editor, I often use the loop function in order to create new rhythms and variations. My idea was to make a shortcut that would allow to copy a selection and paste it directly in the next pattern block (or cell), to make it a cumulative cell of a variety of selection made below.
Originally, I first thought developing a full sequencer, that would allow to re-arrange patterns using this loop function, extended to all tracks, all steps in the sequencer (more of a global re-arrangement tool). While this idea is complicated to achieve for me, because I need more time to learn about scripting; I thought making it simpler, and so, a shortcut.
I wanted first of all, to know if any tool has been made with this idea before.