Ahh, those "things"...

The 28mm f2.8 isn't bad, I bought one before I knew anything about decent gear and revisited it recently. Colours are a bit washed out but it's decently sharp, apparently it's identical to the later version of the Pentax-M lens but with simplified coatings. It lurks in one of the reserve flight cases as I have the K and M versions of the 28mm f3.5 which are much better. K is slightly sharper but M is smaller and easier to find.

I hear the Tak Bayonet 135mm f2.8 isn't too shabby either. That's about it. The rest are definitely a case of being able to do much, much better for the money if buying used!