His top fifteen is very focussed on price, which is fine.
For what it's worth, these are mine. Listed in order of decreasing angle of view on their native format rather than favouritism, as I'd hate to offend any of them
HD Pentax-DA 10-17mm f/3.5-4.5 - versatile, fun, and now more than useful on Full Frame.
Laowa 12mm f/2.8 Zero-D - as wide as it gets and remarkably well corrected.
HD Pentax-DA* 11-18mm f/2.8 - as good as the DFA15-30 and far more practical.
HD Pentax-DFA 28-105 f/3.5-5.6 - compact, cheap, and over-delivering.
SMC Pentax-DA 21mm f/3.2 Limited - a tiny jewel in the Pentax crown. I prefer it to the DA15.
SMC Pentax-FA 31 f/1.8 Limited - compact for what it can do. Epitomises what makes Pentax special.
Sigma 35mm f/1.4 Art - just a fantastic optic.
HD Pentax-DFA* 50 f/1.4 - the best lens I've used.
SMC Pentax-FA 77 f/1.8 Limited - see what I said about the FA31, and double it.
SMC Pentax-DFA 100mm f/2.8 Macro WR - the honorary DFA Limited
SMC Pentax-FA 135mm f/2.8 - the smallest, fastest and closest focussing of the 135's.
HD Pentax-DFA* 70-200 f/2.8 - THE pro zoom.
HD Pentax-DA 55-300mm f/4.5-6.3 PLM - THE consumer zoom.
SMC Pentax-DA* 300mm f/4.0 - gob-smacking IQ dressed up with DA* class.
DFA 150-450 f/4.5-5.6 - too good to be believed until you've used it.
Warming the bench are the SMC Pentax-DA 15mm f/4.0 Limited, SMC Pentax 28mm f/2.0 and the SMC Pentax-FA 43mm f/1.9 Limited.