Buttons in their respective menus tend to pile up, especially when using plugins.
It would be great to have not only a chance to bring the buttons into an order that makes sense but also goup items that logically belong to each other by putting dividers and flexible spaces to separate them from the next group fo buttons above or below / left or right from them.
None.
Would love this feature as well. One of the recent insider patches has allowed us to change the order of the buttons but having dividers and, my preferred option, flexible spaces would make it even easier to make the app look and work exactly in the way I want it.
Would love to put canvas/excalidraw a bit lower then the rest, have a middle group of “sometimes” tools above them and then search, daily note and other highly used buttons at the top.
Just submitted a plugin for this functionality today! Waiting on the Obsidian team to review as part of the existing review backlog. 
Repo: GitHub - andrewmcgivery/obsidian-ribbon-divider: A plugin for Obsidian.MD that allows you to add dividers to the ribbon to space out your icons. (can get early access via BRAT)
Submission: Add plugin: Ribbon Divider by andrewmcgivery · Pull Request #2788 · obsidianmd/obsidian-releases · GitHub
Oh! That looks VERY COOL!
THANK YOU THANK YOU THANK YOU!!
When will it be in official Rep?
Judging by where they are in the queue, I would guess 1-2 weeks, including some back and forth on the review itself.