DA 50 f1.8 - First fifty I bought for the Pentax system. Whenever the new 50 1.4 comes out, I'm hoping to upgrade this one right away. It's a decent lens for the money, but isn't great on ff imo.
Helios 44-2 f2 - Bought it for my previous system (oly mirrorless), very nice for the price, but because I have th 44k-4 it sees no use, and I might sell it.
Helios 44k-4 f2 - found it attached to my old Zenit SLR, very pleasant surprise! Sharper than 44-2, virtually identical swirly bokeh, and it's a native K-mount, so it will stay in my bag for years to come
Pentax-A 50 f1.4 - most recent purchase. Haven't had the chance to properly test it, but it seems to be a nice and very compact lens. Seems sharp enough wide open in the short amount of time I had with it, will stay in my bag.