These lists can get quite long.
May i suggest. You try and find a like minded person in your locale
Who might be able to pront spare parts if you have a problem.
No particular order...
Heater 24v for mk3
Bed and extruder thermistors
Left hand noctua fan
Front part fan
Heat shrink tubing.
Flexible wire. For heatbed pinda and motor wire repairs
Soldering iron and solder
Ptfe tube... pencil sharpener and taper cutter /reamer
Spare grub screws motor gears. Bondtech and hot end thermistor
Spare 3mm cap head screws
Pei sheet limmonene
Ipa and acetone
Disposeable paper towels
Sponge with Green kitchen scrubber
Spare SD card
Flush cut wirecutters
Hex keys ball end...
Thars a starting list
I try to make suggestions that I believe to be well founded and safe,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions,
what you do, is YOUR responsibility.