Raspberry Pi GSM/GPRS/GNSS Bluetooth HAT Expansion Board GPS Module SIM868 Compatible With Raspberry Pi 2B 3B Zero Zero W Support Make a Call,Send Messagess,DataTransfer - Newegg.com
A9 GSM/GPRS Module - DFRobot
SIM800A - GPRS GSM 900/1800 Mhz Module
M590E SMS GSM GPRS module 900m-1800m sms The message DIY kits for Arduino
Amazon.com: GSM Shield, SIM800L Module GSM GPRS Module with Antenna Replacement GSM Module for SIM900A : Electronics
Amazon.com: GPRS/GSM Development Board Module Kit, SIM Development Module, Power Supply SIM card Data Transmission for 850/900/1800/1900 MHz - USB-TTL, Quad-Band, AT Commands : Electronics
Amazon.com: SIM808 Module GSM GPRS GPS Development Board + IPX SMA GSM GPS Antenna Support 2G Network for Arduino Raspberry Pi : Electronics