Ahaha the Pokemon GS VC release title IDs are pretty damn suggestive....https://t.co/nTFeNQZS8k -- Gold, Silver, Gap, Gold, Silver, Gap, ...— Michael (@SciresM) September 13, 2017
ahahaha they left the patches for Pokemon Crystal's VC release in the GS VC ROMFS -- "CGBBXTJ0.534.patch". Classic.— Michael (@SciresM) September 21, 2017
While not an official confirmation, some 3DS eShop behind-the-scenes snooping has lead to speculation that Pokemon Crystal might be added to the 3DS VC at some point. With Gold/Silver hitting the service, it wouldn't be too surprising to see Crystal follow sometime after. I guess we'll just have to wait and see!