It depends a lot on the venue, both in terms of what works and what they will allow. If you can feasibly use a stand, all you need is a stand, a mic bar (and mic clips), long enough cables, and some velcro strips (or whatever) for cable management. If you want to be prepared for whatever various situations you may encounter (on-stage, clamping, small footprint), the list grows.
I would suggest the following; they are all Manfrotto part numbers but there are similar items available from a bunch of other companies, like Impact. So: 1004BAC (stand that goes pretty high and you can adjust the footprint within reason), an 035 (SuperClamp), a 386B-1 (NanoClamp), an 003 (stand base), a 122B (short extension pole), an 099B (long extension pole), and an 026 (umbrella adaptor). Plus a bunch of spigots and some rapid adapters. Safety cables for any clamping. Add in a 6" end-grip Mathellini clamp, and you are good to go for basically any situation you would usually encounter, from low-profile on-stage (003 plus a spigot plus the bar); to clamping up, down, at an angle, or to another stand (one of the clamps, maybe an extension pole, maybe a rapid adaptor, maybe the umbrella adaptor for non-right angles), to limited footprint spaces (003 + 122B + 099B). The engineer/tour manager for Julian Lage calls it my "TinkerToy set". Of course, I try not to carry all of that stuff, but sometimes you have no clue what you will encounter.
For mic bars, with extensive flexibility and great quality at a (comparitively) reasonable price, try Robert at
https://mikrofonschiene.de. The "Basic AB" or "Set 1" would probably be good options, with extra screws as needed.
Lastly, I would suggest making at least a few runs with just a pair before you leap into multiple pairs (especially given wide-ish cards and omnis). The first few times can be a little stressful, even if you have practiced in the living room. Add the hassles of unanticipated venue requirements, people running around, and a dark room (small flashlight, by the way), and it can be a challenge at first.