A simple AutoHotKey (v1) script to map controller buttons unused by Switch emulators to external hotkeys.

SwitchMap.ahk

DisplayHelpMsg()

Joy14::  ; Share button = F8 (Ryujinx screenshot)
TrayTip Screenshot Captured, A screenshot has been saved to the Ryujinx screenshots folder.
Send {F8 down}
KeyWait Joy2
Send {F8 up}
return

Joy13::  ; Home button = Alt + 3 (Shadowplay)
Send {LAlt down}{3 down}
KeyWait Joy2
Send {LAlt up}{3 up}
return

#F::  ; Exit script = Win + F
Gui Destroy
MsgBox, 0, SwitchMap - Exit, SwitchMap is now closed.`n`nDon't forget to disable Shadowplay's Instant Replay feature (Alt + 2) before finishing up!
ExitApp
return

#D::  ; Help dialog = Win + D
DisplayHelpMsg()
return


DisplayHelpMsg()
{
    MsgBox, 0, SwitchMap - Mappings, Screenshot:`t`tShare (Joycon)`nLast 30 Seconds:`t`tHome (Joycon)`nDisplay this help box:`tWin + D`nExit script:`t`tWin + F`n`nDon't forget to enable Shadowplay's Instant Replay feature (Alt + 2) before getting into it!
}