Literally anything you like, plus a coating of Nikwax Visor Proof. Costs a tenner but nobody has ever managed to finish a bottle, it’ll last you forever. Just spray, wipe, dead easy, do not get it on a linoleum floor or you’ll die next time you walk on it in socks. It also helps water to run off, though you need to be going fast for that to really work.
It’s more effective than any factory coating ime. But some glasses are naturally sweatier/have less airflow so that comes into it too, I hate having airflow over my eyes so I like close and protective glasses and that does mean they might still fog up no matter what you do. Ventilated or more stood off glasses are better for fog, I just never found it to be worth the tradeoff