TL;DR

game-icons.net is a fine resource for icons, let’s put them all together in a directory.

If you’re looking for a lot of icons with a consistent style and that you can use under the CC BY 3.0, you should definitely give game-icons.net a look.

Here’s a few personal considerations:

• plus: as of this post, there are 3817 icons;
• plus: the license only requires attribution, which is fair IMHO;
• plus: icons are available in both PNG and SVG format (which also provides amazing resizing capabilities, of course);
• plus: you an get all icons in a single sweep (the ZIP archive for SVG icons is less than 4 megabytes);
• cons: metadata (e.g. categorization into tags) is not available for download.

Another big plus is that every icon is basically formed by two paths, one square for the background and one shaped for the foreground. Which will be more interesting in the days to come.