I don’t know about the single-best looking knight; for one, the knight has to fit the other chess pieces. But I think the knights of the Austrian Coffeehouse reproduction are really beautiful. They’re elegant, lifelike, and I like their asymmetry with the mane going to the left side.
I also really enjoy Soviet knights, which show quite a diverse range of attitudes and eccentric designs. One knight I’ve been really enamored with is the reproduction of the 15th-century Novgorod knight in the Jacobson Handmade Chessmen set. Arguably more of a hybrid between a xenomorph and Anubis, but how cool is this? Even a bit goofy with that tongue sticking out.
I also really enjoy this knight from a 1970s “Gabrielez” Spanish Staunton set owned by Vikhram Ravi. I like its small muzzle. The head reminds me of something, although I don’t know what. Maybe some character from the Dark Crystal, or some other fantasy-themed work. Either way, I like how dreamy it looks.
The Gabrielez knight is also quite nice!
I like the Knights from my old Botvinnik-Flohr 2 set. They look more like puma (cougar) than a horse head. They are also well-balanced with just the right weight for their size and the set matches my 2.25" board.
Yeah, beautiful! Interesting how diverse the Botvinnik–Flohr II knights are though. I found quite a few with knights like the ones below, which I find attractive as well.
I also like the Baku knights, which are related to those puma knights of Botvinnik–Flohr II.
The Valdai (Nobles) knights seem related as well; they’re like faceted pumas.