Chocolatey - The sane way to manage software on Windows.
AppSales - Find the best Android apps and games from Google Play that are currently discounted or free for a limited time
WAPT Community - Deploy your software and configurations, perform an inventory of your machines in real time, control Windows Updates and benefit from customized reporting of your IT assets
Fnd - Browse Apple App Store and iTunes on the Web
Just Install - just-install - The stupid package installer for Windows.
TheAppStore.org - Find apps by rating, price, category, updated date and more