I read somewhere that Chinese "ma" for horse and English "mare" might be related, originating from a steppe people of horseriders. I find these possible connections from time immemorial really fascinating.
In Indoeuropean it's only present in the Germanic and Celtic branches (Protogermanic: marhaz, Protoceltic: markos), but in the Far East, as well as Chinese 馬 (mǎ) there's Mongolian морь, Korean 말 (mal), and Japanese うま (uma).
I can't find any Finno-Ugric or Turkic cognates, so it looks like there are two separate clusters.
At least the Finnish etymologic dictionary says it's related to Aryan words, e.g. medhu in Sanskrit.
https://kaino.kotus.fi/suomenetymologinensanakirja/?p=qs-art...