What is the best set of older manual focus lenses that are great quality and affordable?

I sold my AF lenses and want to pick up an adapter and some bargain (but great quality) older lenses.

I want them to be all the same brand as I only want to buy one high quality adapter and not several different ones.

Nikkors seem nice but overpriced, I am thinking maybe older Olympus or Pentax glass. Keen to get other opinions though.

I only want a few primes.