[Bystroushaak]

I usually have Structure side panel[1], which shows all of the definition signatures (classes, variables and functions), and probably the thing you mentioned (CTRL+r on linux), and also if you double press shift, it will do a semantic search trough the whole project.

[1] You can see it on the left https://blog.rfox.eu/en/Programming/Tools_I_use/Tools_I_use_...