I nominate the SMC Pentax-DA* 300mm F4 ED [IF] SDM
https://www.pentaxforums.com/lensreviews/SMC-Pentax-DA-Star-300mm-F4-SDM-Lens.html
I use this lens for my professional college and high school sports action photography and wildlife photography, as well as many other subjects. The quality of the glass is top-notch, the weather-proofing is essential and really good for our Minnesota winters, and the focus ability helps me capture the action in clear, precise shots. I have or have had 8 Pentax or Pentax mount off-brand lens since 1983...the DA* 300mm f4 is one of my go to's.
I am attaching a shot of an eagle we had in our yard about a month ago. Let me know what you think!