Feedback Feature request: Collapsible groups inside the inspector

I have some scripts that have very long lists of variables I can access within the inspector. It makes things a little cluttered and hard to navigate.
It would be nice if I could set some variables to be within certain "groups" that could be collapsed/expanded so that I only need to see the variables I actually want to work with.

Here's an example. This is a screenshot of on of my player classes:

Rather long and convoluted.
But what if I could make it look like this:


Much cleaner and easier to organize!

I imagine this working by declaring a simple tag above any variable in the script, similar to how I can state "serialize" or "hide in inspector," or add a header attribute.
Also, I would appreciate it if these groups could be arbitrarily collected from any specified public/serialized variable. So say for example I have a group of variables I made for one class, and then I made another class that extended from the first class. It would be great if my second class could have some of its variables included in a group that was made in the first class. That would make it easier to organize variables according to any arbitrary design I want, so if I have a new variable that makes sense to add to an existing group, I could still do that.
But if cross-class grouping can't be done, I would still be satisfied just to make groups so I can hide variables I would rarely change.