This is only a few hardcoded keys I've found so far. I.e. they can't be rebound or follow the keys that logically should be the same.
Respawn Map
A and D for cycling through spawn points available. Separate bindings for this could be nice, but following your character movement left/right keys would make sense.
Switch Radio UI popup
When pressing the 'Select active radio' button (default G) the buttons for 'Next Radio' and 'Turn On/Off' are hardcoded to G and R respectively. The 'Next Radio' should probably be the same key as the player used to bring up the UI like in the defaults. The 'Turn On/Off' should probably follow the key for 'Use Item' (probably preferred) or 'Reload' also like the default.