As you know, Pentax flashes are rare and expensive. I have a Yongnuo flash for my Nikon DSLR and it's great and reasonably priced. I bought this for my Pentax K5 and I am very satisfied. TTL is very accurate and has many manual power settings. Very high-quality workmanship, without cheap materials, non-slip. Worth a try.
Nissin I40S Camera Flash Black
9 Review
Wireless Macro Twin Lite Flash - Meike MK-MT24S for Sony MI Hot Shoe π· Mount Mirrorless Cameras such as A9, A7III, A7RIII, A6400, A6300, A6000, A6500, A6600 and more
11 Review
Enhance Your Photography with the Olympus FL-600R Wireless Flash
9 Review
Godox TT685F Speedlite Flash for Fujifilm - 2.4G TTL, GN60, 1/8000S HSS, 0.1-2.s Recycle Time, 230 Full Power Flashes, 22 Power Output Steps
10 Review