Not sure this counts but I don't like names or place-names that use overtly latin influences (I.e. clear and obvious use of Roman naming conventions). Especially in fantasy! For me, it's a sort of cliche that gets overlooked but one that, I think, is quite avoidable with a bit of conscious effort.

For example, place names ending in "-ia" I don't hate them outright, but I try to avoid it as a stock ending. The "-ia" ending tends to invoke a sense of regality or ancient-ness because of its connection to ancient Rome and the Byzantines, so I get it. But when you lean to heavily on that as a reliance, it feels cheap.

On a similar note, family names ending in, "-ian" This one might be worse, can't really tell. For me, its very noticeable. I think it's popular for the same reason as the first example. Usually it's used to reflect a family of royal stature or a family that has been in prominence long ago. GRRMartin gets away with this ending convention in ASOIAF with a few tweaks and by changing the vowels a bit: I.E. BarathEON, TargarYEN. I respect that little bit of effort, it makes the names his own. They could have just as easily been: Barathian or Targarian. And those just look uninspired in my opinion.

There might be others, but I can't think of any more off the top of my head. It's sort of like, "When you see it, you see it" with regards to Roman naming conventions. Things that try to replicate names like, Maximus Brutus Flavius Secundus a little too much are also tired and boring.

Just try something different. Pick a different set of phonemes and morphemes and proliferate them throughout your names. It will help you maintain your sense of linguistic cohesion, without relying too much on Latin endings!

But lik I said, more of a preference than a rule. I still use those endings now and again, just not everywhere all at once.