You should really learn how to use the site search function. Since you are new here, this should help you get started.
Here's the two primary cards that fit in that slot. It's not really possible or recommended to use adapters.
- Half mini: BCM94360HMB/AzureWave AW-CB160H - native WiFi/ac and BT4LE (3 antennas)
- Half mini: BCM94352 HMB/AzureWave AW-CE123H - supports WiFi/ac and BT4LE
Broadcom WiFi/Bluetooth [Guide] WiFi and Bluetooth working out of box on macOS with Apple branded Broadcom BCM94360. Enables specific half mini and M.2 BCM94352 on macOS with methods described below. Credit: RehabMan This thread does not support: macOS/Continuity Atheros/Qualcomm...
www.tonymacx86.com
Amazon has the BCM94352HMB/AW-CE123H for around 30 dollars:
https://www.amazon.com/gp/product/B00HRFS1GQ/?tag=tonymacx86com-20
Lowest price right now is from this seller in China:
Find many great new & used options and get the best deals for Wireless AC1200 Broadcom BCM94352HMB AW-CE123H 867M BT4.0 MIni PCI-E Wifi Card at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Ordering from Amazon is the fastest and safest way to get one. Also much easier to return it if you need to.