In no particular order, Davies, Robertson, Theo Hernandez, Telles, Alba, Lodi, Ferland Mendy, Tagliafico, Digne, Chilwell, Alex Sandro, etc. Obviously Reguilon had a better season than some on this list but I'd not put him ahead on that basis alone given his limited first team football overall.
I like Reguilon a lot but no offence, for me it's crazy to say he's the 3rd best LB in the world. It's also important to consider the context of the league - not sure Reguilon would be an ideal fit in the PL. Furthermore, a big part of why we're after Chilwell is his ability in the air - he's the best LB in the PL and among the best in Europe aerially.