Duilio Loi, reknowned as a southpaw but from the footage available boxed only orthodox. Interesting case. Either way, the results can't be argued with. Beating a prime Carlos Ortiz in 2 out of 3 fights (and arguably the other as well) is as good as it gets in a series.
cotto's good off the top of my head but not atg im sure.. another honarable mention is alfredo el perrro angulo..
Andre Ward is the most natural switch hitter today. The way he steps into the southpaw stance after throwing a right hand...that is magic right there. Cotto usually switches up so that he can use his left as his power hand when pounding a guy on the ropes.
Omar Figueroa’s defense is lacking, but he switches and is a great attacker from either side, especially to the body. Hagler is the master. Could box or slug either way.
switch hitting is to fight ambidextrous? The best ambidextrous fighter ever, imho, is marvin hagler. The best active ambidextrous fighter now, is crawford.... hands down! no doubt at all.