Product Hunt - A website that lets users share and discover new products
Transferslot - Easily buy and sell side-projects
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
To Build Something - Find side project help and collaborators
BetaList - BetaList provides an overview of upcoming internet startups. Discover and get early access to the future.
Solodoers - Get matched with a side-project you want to scale