In general English language use ascot and cravat are pretty much the same, with AmE preferring ascot while BrE preferring cravat (for the modern garment).
On Danbooru, they appear to describe different neckwear; both ascot and cravat have slightly different definitions. In particular ascot seems to place emphasis on having two "wide-tipped" tails. Though this now sounds like it overlaps with neckerchief.
In practice... both tags seem to be used all over the place, usually for "frillier" neckwear that don't seem to fit under neckerchief (the ones that European noblemen are noted to wear). Occasionally some posts are double-tagged with both ascot and cravat for the same neckwear e.g. post #4620242 (that I think is an earlier 'cravat').
So... I think we need to disambiguate those tags somehow. Or merge them. Any thoughts?
Edit:
Overall, seems like:
- Cravat gets used either for the frilly ruffled neckwear thing (what Wikipedia calls a Cravat_(early), or the old style non-frilly cravat that resembles a 'broader' necktie (also looped in together under Cravat_(early) on Wikipedia).
- The neckwear worn by certain Touhou characters (e.g. Flandre, Reimu) don't usually get tagged cravat (nor neckerchief). These tend to be frilly or have folds, but aren't as ruffled as the 'European nobleman cravat'.
- Meanwhile ascot gets consistently used for the abovementioned Touhou neckwear. But it also gets plopped down on the extra-ruffled 'European nobleman' "cravat_(early)" thingy. And sometimes for side-tie neckties or any of the ones with broader tips (i.e. what would be described as an "ascot tie" in modern American English).
Updated