I think I've heard of some folks having luck with Atheros cards, but I don't know if any card gets 802.11ac speeds. For example, I have a multiboot laptop with an Intel 7260. FreeBSD can run it on the 5GHz channel but at best, I've gotten 12 MB over the LAN and that was unusual. Generally, it gets 2-5 MB. In contrast, on Linux, it gets 30-50 MB on the LAN.
