Take a look at the Actions list. You can use
Filter to search for specific actions and
Find shortcut to see what is currently assigned to any key.
Kennys video about Actions:
http://www.reaper.fm/videos.php#tzg9fifza0s
There are also couple of old Nuendo/Cubase style keymaps if you want to try them, like this one:
https://stash.reaper.fm/v/3139/Nuendo...s.ReaperKeyMap
Check Reaper User Guide 5.40c, 15.13 Exporting and Importing Keyboard Shortcuts (page 293). Welcome to the boards Phil.