GSMArena - GSMArena is an online site that offers exhaustive and up and coming cell phone data.
Mac of all trades - Mac of all trades allows you to buy cheap refurbished Apple Computers and Laptops at the Lowest Prices with a Free Warranty, which covers the product in case of damages.
NanoReview - Most advanced CPU and SoC comparison
Apple - Available on iOS
Productz.com - Crowdsourced products database
EveryMac.com - EveryMac.com is an online website that provides complete details about every iPad, iPhone, Mac, iPod, and Mac clone made by apple.