What you will definetly need is a set of screwdrivers and allen wrenches. Plus a fine gauge, like a milimeter gauge (I for one use a piece of paper I cut out of those sheets with milimeter squares for technical drawing). Also a wirecutter.
With that you can do the basic stuff: Change strings, adjust neck relief, adjust bridge height, adjust intonation and set the pickup and polepiece height.
Adjusting the nut height is harder to do, but youŽll need it very rarely. I canŽt do it too and never needed to.
Nice things to have imho are: A fret cleaner (I use one which is a special kind of cloth, brings the shine back with some rubbing), a fretboard cleaner and a conditioner (I use the dunlop ones) to clean and get the oil back in the wood.
Also I love what Feline recommended me at one point which is the Nutsauce tuning lubricant. Graphite from a pencil on the nut will get the job done too, but this works quite a bit better imo.