NodeMCU Development Kit with ESP8266 Microcontroller
Not really the new product, but one of the essential ones. This is NodeMCU AKA ESP12E development board with the ESP8266 microcontroller onboard.
NodeMCU is an open source Lua based firmware for the ESP8266 WiFi SOC from Espressif and uses an on-module flash-based SPIFFS file system. NodeMCU is implemented in C and is layered on the Espressif NON-OS SDK.
The firmware was initially developed as is a companion project to the popular ESP8266-based NodeMCU development modules, but the project is now community-supported, and the firmware can now be run on any ESP module.
Available at Amazon for $6.99
ESP-01S Board with USB to UART Adapter Module
ESP8266 microcontroller also available on a small board with EEPROM, oscilator and a few essential components to make it functional. This board called ESP-01 or ESP-01S and it comes with 8-pin connector. You will need a simple USB to UART adapter to program this board from any computer via USB port. You can purchase the kit with the ESP-01S board and the adapter from Amazon for about $10.99, but be warned that there are some adapters out there that don't have the switch and pull-down/up resistors for proper communication with the microcontroller board.
The link below is for the correct adapter which have the programming switch.
Sensors and Other Boards
Although the items below have nothing to do with ESP8266, they can be used with the two microcontroller modules mentioned earlier.