Factory reset
Recovery mode update
NTRBoot
Most of these are already available as part of the boot process, having them in a menu would just make them easier to access.
It also closely mirrors the Switch recovery menu (with the addition of NTRBoot)
There isn't much more you'd expect to find in a recovery menu, and having things like firmware flashing or backup (like Android) would just introduce another potential entry point for exploits.
There is another thing I could imagine being useful, that being an option to re-run the first time setup. Basically allowing someone to quickly set up the console as new, without wiping data (such as preinstalled games). Could be incredibly useful for second hand consoles, but probably wouldn't be useful to Nintendo service techs so it would never actually be in an official recovery menu.
Format SD card could also be useful to have in a recovery menu, but probably wouldn't be since it's not on the Switch and it's not a necessary feature (can just format the card on any PC)