HippityPip - Teach phone numbers to kids
Steam Inventory Helper - Steam Inventory Helper is a free browser extension for Google Chrome that adds a big amount of new features into the Steam trade-offer system & Steam store functionality.
Battle of the Brands - Compare the online awareness of 2 brands in a battle
Augmented Steam - Enhanced Steam fork by IsThereAnyDeal.
Hatch - A subscription service for Gaming
Steam Tools Hub - A set of Steam related WebApps built around trading cards, emoticons and backgrounds.