Arduino USB-to-Serial Tutorial - Programming the Pro Mini - YouTube
Arduino USB 2 Serial Micro - Corzotech
Serial USB Converter (5V/3.3V selectable) - SWITCH-SCIENCE
Arduino programming by USB to TTL converter - YouTube
Using a Pololu Programmer v2 as USB to Serial for communicating with an Arduino Uno R3 - Other Pololu products - Pololu Forum
Yizhet 2PCS USB to TTL Serial Converter with 5 PIN Jumper Wire Cable Chip Compatible with CP2102 Arduino, Windows 7, 8, 10, Linux, Mac OS X: Amazon.co.uk: Computers & Accessories