There is also no way to rearrange your containers aside from deleting them and making new ones in the desired order. Since I am using this for o365 administration it is a little annoying that I can't keep them in alphabetical order to find them easily.

Are you on the latest version? I can rearrange them on mine. If click on "manage containers" there is a gray on gray bar on the right. If you hover it, your cursor should change to an arrow to rearrange them.

That allows for visual rearrangement of that particular menu, but as far as I can tell the new tab button's list does not change and the extension keyboard shortcuts are still limited to the first 10 containers, which are bound by their creation order.

A non-sanctioned way to mitigate this might be achieved by editing containers.json, but I'm wary of inviting sync shenanigans.

This is something that I don't like about firefox. They have a ton of cool stuff, but I feel that they are always lacking a few things.

What I always give as an example, is how to add custom searches (Amazon, Reddit, HN, etc), you save the query url and add a keyword. Works very well to type `rdt something` and have the results. But: there's no option in the menu to see all keywords/search engines you have registered.

My workaround for this is to title the bookmark, e.g. "kw:rdt Page Title".

Imperfect, but the convenience is worthwhile for the dozen-or-so keyword searches I use.

Yeah, but that's kinda the point: seems that there's always a need for a workaround. Also, I know I'm going to forgot to rename a bunch :/

Yes there is. Saved keywords are just (Parametersteuerung) bookmarks so open the bookmark manager and you will find them.

I know they are bookmarks. But the point is that there is no way in the bookmark manager to filter bookmarks that have keywords.