hostapd
learn.adafruit.com/ Setting up a Raspberry Pi as a WiFi access point
www.psattack.com/articles/20160410/ Setting up a Wireless Access Point in Kali
$20 at amazon Alfa AWUS036NHA Wireless B/G/N USB Adaptor - Atheros Chipset
In my experience, the Wi-Fi chipmaker with historically the most vibrant open source community is Atheros (now “Qualcomm Atheros” or “QCA”). So look for adapters that use Atheros chips.