An 11-in-1 with Robertson or Combo tips is a lifesaver.
Only a couple of my combos have Square / Robertson, Slotted, and Phillips by default:
Craftsman CMHT68129 Precision ratchet screwdriver The following bits are present:
S01|S02, T30|T25, T25|T20, PH3|PH2, PH2|PH2, PH2|PH1, and 1/4"|3/16". There are two T25 and four PH2 bits.
Megapro Original 15-in-1 Multi-Bit Screwdriver. This is the original driver with the following bits:
0 – 3, 1 – 2 square. PH0 – 3, PH1 – 2, Slotted 4 – 6, T10 – 15, T20 – 25, and ¼" hex nut driver. I don't care much for this handle but it does get the job done.
Megapro Amigo Has Bit Sizes PH1 – 2, Slotted 3/15 – 1/4, and
Square/Robertson 1 – 2. I have 4 colors. This was the big surprise of the day, especially since I find these comfortable and I paid $3 each for these.
LTT 12-in-1 Multi-Bit Ratcheting Screwdriver includes Phillips (PH-0, PH-1, PH-2) Hex (#2, #2.5, #4) Slotted (2, 4, 6)
Square (S-1, S-2) and a Magnet bit (more helpful than you would think).
If I did this often, I might take one of my PB Swiss combos and just add the bits I want; for example, if I wanted pozi in the mix. PB Swiss does not include the Robertson / Square drives in a multi-driver of which I am aware.
I don't know if anyone else does this, but I often save screws out of old devices, or any extra screws that come with mounting kits, etc. I like having spares, so if one is stripped I can replace it. I have far more screws than I will ever, ever need.
I have been doing this for years. I might go years without needing something specific and then I suddenly need 8 of them. Of course, when I just get too many of them I throw them away, but otherwise I embrace my hoarder tendencies on this. If they get in the way, pitch them, if not, well, it can save a bunch of time to not have to run out and get something.