Style variations are very neat and we are adding a few more in 4.0 and 4.1. We currently show them in the block switcher, which is great, but it seems we should also show them on a panel in the sidebar called "Styles" for maximum discoverability.

This would be in addition to the block switching mechanism not as a replacement. The code should be reused entirely, except for the hover previews maybe.

Mockups

Note that these mockups are not pixel precise.

Variations in the sidebar:

If you were to open both at the same time, just to make it clear both interfaces are available: