Yeah, Grand Cru is just a "this is a flagship beer for our brewery" thing. It's mostly used by Belgian breweries, so most "Grand Cru" beers are a Belgian variety (Tripel/pale ale/witbier/Strong Dark/Strong pale/etc), but not always.
e.g. Diekirch Grand Cru is a Vienna lager
It's kind of like putting "Brewery Reserve" on the label. Feel free to use it for whatever beer you're proud of yourself!
On deck: Little Bo Pils, Bretta Off Dead (Brett pale)
Secondary: Oude Bruin, Red Sky at Morning (Sour brown ale)
On tap: Saison Duphunk (sour), Amarillo Slim (IPA), Earl White (ginger/bergamot wit)
Bottled: Number 8 (Belgian Strong Dark Ale), Eternale (Barleywine), Ancho Villa (Ancho/pasilla/chocolate/cinnamon RIS), Oak smoked porter (1/2 maple bourbon oaked, 1/2 apple brandy oaked)