Connecting Wi-Fi on Raspberry Pi Pico Become Easy - Hackster.io
Arduino IDE in Raspberry Pi 3B+ with ESP8266 Nodemcu - Som Tips
ESP8266 WiFi Module for Raspberry Pi Pico, WiFi Expansion Module Controlled via UART at Command, Support TCP/UDP Protocol,STA, AP, and STA+AP Three WiFi Operating Modes
ESP8266 IoT Enabled WiFi HAT for Raspberry Pi Pico from SB Components on Tindie
Raspberry Pi WiFi With The ESP8266
Interface ESP8266 WiFi Module with Raspberry Pi Pico - Web Server
$6.95 - ESP8266 Serial Wifi Transceiver (Arduino & Raspberry Pi Compatible) - Tinkersphere
Raspberry Pi Pico Essentials: A Project with Wi-Fi, the Pico, and a Smartphone | Elektor Magazine