>>3130355135mm f2.8 are really common in M42. I do recommand the Beroflex and the Vivitar (but beware, there are many lenses branded "Vivitar" and I can't tell how to identificate this one). The Carl Zeiss Sonnar in C/Y is a must have. The Jupiter-11A is somewhat a sleeper lens, basically a Helios 44 in 135mm with Zeiss inside™. Avoid the Pentacon and the Takumar f2.5.
One rare and interesting lens is the Sankyo Kohki -Komura- 135mm f3.5 too -weak contrast and prone to flare but excellent optics and bokeh.
