Definitely Montblanc/Minerva. The finishing punches to top level but secondary prices are weak.
JLC especially in the 2010s. I would look out for a good deal on an extreme lab 2 or amvox 2. A DSA American Ed would be a good find at the right price.
GP is also a good one. The previous skeleton dial lauretto can be bought for a fraction of the retail price on the secondary market. Anything with 3 bridges too.
H Moser. I think an older Mayu or newer Streamliner chrono are great buys ATM.