When comes to XIV villains, Zenos is far and away the most iconic.
Nah.
Let's go through the list of villains:
Bahamut: he was a non-character, effectively a force of nature. That's actually the only thing good about Zenos he only has relevance to 1.0 players Or any Final Fantasy fan and those who did the Coils, which is content the vast majority of players have never touched. Best raid story. Also has more motivation than Zenos. Actually went through pain, hunted and imprisoned by Allagans. There's at least some adversity. Deeper than Zenos
Gaius van Baelsar: Appears in a grand total of 3 cutscenes in 2.0, and isn't even the final boss. Was one of the only few good things about 1.0. Had legit motivations. Enemy of my enemy is my friend. Deeper than Zenos.
Ultima Weapon: A non-character. Indeed. Literally a tool, a mechanism. Not a character.
Lahabrea: is a pretty forgettable generic evil guy. Only becomes somewhat interesting in retrospect once ShB dropped. Not even then really. Pretty cheesy use of Thancred too.
Thordan: is a generic evil JRPG pope. Nope. His arch is effectively a reference to the cold war. You don't stop going to war just because "war's bad mmmkay." Doesn't matter the truth. The truth remains that Nidhogg is an existential threat unwilling to listen to reason. The entire Heavensward story arch is effectively a metaphor for the Cold War and nuclear disarmament. WoL defeating Thordan was START 1. Hraesvelgr defeating Nidhogg was START 2.
Nidhogg: is a generic evil dragon. He has so little characterization that he borders on being a non-character. Wrong. Sister murdered. Also, since you list Emet below, Nidhogg's motivations are literally no different. The value they put on their own kin is rationalized through longevity / immortality (Nidhogg) or Completeness and Truth (Emet-Selch) if you think Emet is worthy, then Nidhogg is worthy by default.
Fordola: is a lieutenant to the big bad and is more heroic than evil.Still deeper than Zenos. Basically Stockholm Syndrome.
Yotsuyu: spiteful, psychotic woman who gets a sob story later on. At least she has a cool character design.Still deeper than Zenos. Same driving force as above.
Varis Zos Galvus: Doesn't do anything of note. Agreed. Exists only to show us how cold Zenos is, still don't care about either of them.
Ranjit: Forgettable. Best thing about him is the video by Fluffystuff. Oh Sheet! It's Ran-jit. Otherwise, is just generic anime enemy trash. Just as bad as Zenos but he at least has a nation to defend.
Vauthry: Served his purpose but isn't memorable. Gluttony and Pride. Two sins in one. Still deeper than Zenos.
The only memorable, good villains are Zenos
nah and Emet
Again, if Emet, then Nidhogg. Zenos is the most classically villainous
Ya, if you think Snidely Whiplash is a "good" villain. How long do we have to wait for Zenos to tie Minifillia to some train tracks. Lame af. , has the most iconic character design
If WoW shoulder pads are "iconic". Gaius was better., and has combat capabilities most adaptable for a fighter moveset
Fordola and Ran-jit also fit this description, quite literally better than Zenos.. He has the most appearances of any villain
... and shouldn't., appearing across three expansions (probably four)
and grows the least., and is treated as the WoL's arch-rival.
... as an empty vessel to fight an empty vessel. Probably the only reason Zenos is written as he is, which is poorly.
The jury is still out on Elidibus. He has the potential to be just as memorable as Zenos and Emet. It looks like they're setting him up to be the ultimate jerk of the XIV setting and the WoL's timeless arch-enemy. We'll see.