There is a Pentax DA14mm f2.8 available
This is the reference page at B&H Photo for the wide angles in K-mount. Prime lenses
SLR Lenses| B&H Photo Video
Bower/Samyang/Rokinon are manual focus
The 2 Sigmas and the Pentaxes are AF
Of the discontinued glass which are rarer (more expensive) and larger due to full frame compatibility.
FA20mm f2.8
FA*24mm f2
the only one wider is the A15mm f3.5 which is manual focus, ultra rare and expensive
You have to remember that the 14mm on you digital is the same field of view on a 21mm on film. They just didnt make that many wider lenses like 10 or 15mm back then.