Kongregate
Best For: Independently-developed games, apps, and community
Adobe Flash: Required for select games online
Types of Games: Online (computer browser) and mobile (App Store, Google Play)
Kongregate offers over 128,000 online games in many categories including action, multiplayer, adventure, strategy and puzzles. Like Big Fish Games, you'll have to create an account to play a lot of games on this website. Still, it's completely free and easy to create one.
When you visit the desktop version of the website, you’ll see ads across the top and bottom of the page while you’re playing games as well as a few on the front page. For me, they didn’t drastically impact the overall experience. If you visit the mobile version of the website, you’ll be redirected to the app store to download games to your device.
Independent game developers can also upload games to Kongregate, which gives you access to thousands of unique titles.
Pros:
Chat with other players during gameplay
Independently-developed games
All content is available for free with an account
Cons:
You have to create an account to play
Games have to be downloaded as apps to play on a mobile device