Vintage Bianchi components
 

I know many Bianchis were equipped with Campagnolo groupsets, but other had "Bianchi" ones. Who made those, as I assume Bianchi didn't make them? Ofmega? Gipiemme?

Yes. Maybe others like Galli but I'm pretty sure you've nailed the two main culprits. Not usually full groupsets either...Ofmega cranks with Modolo brakes was common.

Like all manufacturers did (in the days before bikes had to have complete groups, thanks shipmano) Bianchi used a little of everything and mixed and matched on bikes for price points and performace.

From what I've seen looking through the '80s catalogs it is almost an Italian who's who of components, GipMe, Ofmega, and Modolo as mentioned, Universal, ITM, TTT, Miche, Rigida and Mavic rims..

Other than Campi the only engraved parts I think is the Ofmega cranks, some ITM stems and I believe TTT seatpost.

Forgot about FB hubs...I think they branded hubs for many marques.

What about the saddles? Did San Marco, Selle or Mul...something do all their work?

If one goes back far enough it is likely to encounter conventional leather saddles from Italia and Rosa.

Oops, I'm trespassing on Rudi's turf here. Time to be quiet. ;)

-----

Mine had a Gipiemme crank and Modolo brakes, bars and stem, but they weren't relabeled or anything like that to obscure their origin.