Analyze
With release 0.20 the ILSpy extension introduces the "Analyze" feature, as known from ILSpy desktop application.
When mouse cursor hovers a type or member in assembly tree, now a magnifier icon appears on right side:
With a click on the button an "ILSpy: Analyze" panel opens at the bottom and presents relations to other symbols organized in a tree view:
Similarly to the assembly tree you can click any entry to see the code of the symbol.