I checked in the Google Forms code but it's not really helping ha ha :D
I would go for a mix between utilites and the way it display.
It seems to be an "Editor Toolbar" that floats and which is sticky to a certain position.
I tried so search about "Sticky Floating Tool Bar Editor" by got a lot of noise in the result. Adding "Google Form" at the end of the search made me found the name "Floating Toolbar" which is short and understandable ; and apparently you would naturally go for this kind of naming.
My thoughts about naming
In term of what you need here, go for a custom name, because in the Google usage, it's a really specific one. I'm not sure you'll find a standard name for this kind of component.
In the Google Form code, I read "Freebird Form Editor". I kind of like it, and I'm sure you can found one for your UI Library.
The thing you need to keep in mind while building a Library, is that this name you choose must be understandable by all the "consumers" of this library. (Designers, Developers, Stakeholders) So… ask them? 😊
Not sure it helps much, if I find better idea I'll come back here.