ESP8266 module comparison: ESP-01, ESP-05, ESP-12, ESP-201, Test Board and NodeMCU - Squix - TechBlog
ESP8266 WiFi Module with PCB Antenna - ElectroPeak
Amazon.com: Waveshare ESP-12F WiFi Module Based on ESP8266 with Built-in 32Mbit Flash in Small SMD22 Package Onboard PCB Antenna and Metal Shield : Electronics