After the caret has been in an identifier in a C# file for a few seconds, then all the usages of that identifier in the current file are highlighted. This provides a nice visual cue for finding related code and following code flow.
There are also commands for quickly moving between these usages. On Windows and Linux they’re bound to Control-Shift-Up and Control-Shift-Down, and on Mac they’re Command-Shift-Up and Command-Shift-Down.