make sure you check around the lugs for small cracks- be sure to wipe away any grit/dirt/grease around bb to check for tiny cracks.
Rear chainstay- I bought a frame that I didn’t fully check and it had a tiny hairline crack which was probably caused from people riding off gutters or riding into potholes.
wheels can be straightened pretty easy but just check for nice big flatspots or again cracks around the spoke eyelets.
Also annoying little things like cables, brake pads and tyres can add up to a sizeable amount if they are all shot.
Also look how much corrosion is around the seatpost or stem- removing a well stuck post or stem can require a lot of patience and can be very annoying if they cannot be removed.
take a metal ruler or something solid and straight to sit up against the tubing so you can see if there are any slight or extreme bends that perhaps your eye couldnt see, this usually is caused by people runnig the bike into a car or other item, forcing the fork to bend the top and bottom stubes. just worth checking.