Do you need pci, pci-E or usb? Want N300 or is 54Mbps OK?
RaLink, prior to being purchased by MediaTek, provided hardware specs to FreeBSD. For usb, pci and pci-E, anything RaLink is usually good. Mediatek is less so.
For pci-E, I also have good performance with rtl8188ce,
One caveat is the little usb nano adapters all look the same but have a multitude of different chipsets - Make sure you have an easy return if dmesg does not concur with what you tried to buy.