Look out for loose screws securing the rocker box covers on Lycomings. Worth giving them a tweak with the plain screwdriver end of your fuel tester when doing the check A. (But try not to burr the screw slot!).
Aileron hinge cracked.
Damaged aileron caused by mishandling on the ground.
Missing split pin in main undercarriage scissor links (post maintenance).
Loose hot air box.
Primer line fractured just below the nut securing the line to the cylinder.
All on a PA28-140.
Have a go at the walk - around check competitions that are held at events like the PFA rally. You'll be surprised at how many faults we miss........