The pentax m series and a series are good.I have a 28mm a series, a 50mm m seires, and a 135 m that are all very good. Small ,compact, well built, good images. All take the same size filters.
I have a screw mount adapter for a few really long lenses, but I think it is more trouble than it is worth. I think I paid about twenty bucks for it, and for that or not much more you can find complete screw mount bodies.
I think any of the older k, m or a series lenses would be worth using.