Mini-screwdrivers; like the ones that Bob Roberts gives for free in his arcade parts orders that have the little pocket clip on them (aka "the eleventh finger"). Indispensable in philips and slotted versions.
I would also submit, that although it might be up one level from "newbie", a decent pair of molex crimpers (and familiarizing yourself with different molex connectors and headers). With pinball, it's only a matter of time before you need to replace a connector.