The Internet archive has been doing some pretty awesome stuff lately, just last week they put every issues of Nintendo Power online and now they have made of 10,000 Commodore Amiga titles available and playable in your browser.
The Amiga collection currently has 10,313 titles. Many of these are well-known games like Double Dragon, R Type, Lemmings, Project X, Kings Quest, and more! While many of these games will work in your browser using the HTML5 emulator, some of them do not work yet. According to a contributor to the collection there is a lot to improve and refine.
If a game or program will not work in your browser you can alternatively download and run the adf files in an emulator like WinUAE.
Check out the Amiga software library here.