Here's my wife curling 80 lbs on the Hammer Strength Curl Machine. Machines are a little easier than free weights though.
I remember Cindy Philips saying in a video that she did bicep curls with 60 lb dumbbells.
There were those strength extravaganza contest around the 90s.
One part of it was strength contests. I think to remember there was a part where they curled 60% of their bodyweight for maximum reps. They are really burning out their biceps there.
MV sells videos, not sure if there is something free available on the net.
Nataliya Kuznetsova (amazonka) curling about 60kg (132lbs) (50kg in plates + 10kg bar) for reps.
Unfortunately I can't find the video or pictures but I'm pretty sure Michelle Maroldo curls 150 for a couple of reps in an old wpw video.
I know Marika Johansson, Nas ranjkesh and Irene Andersen can do 60kg biceps barbell curls. Tbh I have been going to the gym consistently now for 6 months I can do 50kg biceps curl. It's not that hard tbh Natalya should be able to lift more than that
Zuzana Kornikova without peers ... tons of pixes on site. Christa Bauch ...