Universal Cartographics would probably be the most important one, since losing your data due to death is something that can't be purchased back.
Armoury, despite it's name also allows an explorer to restock any SRVs/SLFs that are lost over the course of their journey, or replenish any heatsinks (Heatsink synthesis require materials found in the bubble). Limpets and AFMU ammunition can normally be synthesized using basic materials which can be collected by most explorers with an SRV, but for those that don't have an SRV, this will be important. This is an essential service IMO if you are planning on mining for Tritium, unless you want to collect the large number of materials necessary to synthesize Limpets.
Repair should be handy as even if explorers do carry repair limpets, the ship integrity can't be restored without a repair facility at a station. It also provides a fresh coat of paint to restore an explorer to that showroom shine long lost in the past.
Refuel isn't quite as important as pretty much anyone out that far is likely carrying a fuel scoop (unless they're doing a no-refuel challenge!), but if you happen to be parked in a particularly sparse region of stars where the distance between stars can exceed the normal jump range of most ships, or if you are deep within a field of stars that you can't refuel from (eg T Tauri stars) this could be a handy service to have.
The above is pretty much the only services I'm looking to purchase for my own carrier, but there might be some niche for those that want to change the outfitting of their ships or purchase a new one while in deep space.
