Right now the Breeze icon theme has no monochrome or colorful icons that connote "Applications." The Breeze Plasma theme has one such icon though: a 2x2 grid of open squares. I don't think this icon does a great job of communicating the meaning, and it looks very similar to the icon used for Icons View in Dolphin and the file dialogs. And it isn't present in the Breeze icon theme, just the Plasma theme. I'd like to propose that we come up with a better concept for an "Applications" icon, and create colorful and monochrome versions for use in various contexts.
The "All About The Apps" initiative has been using the `homerun` icon, which is a colorful 2x2 grid of squares. I guess we should just go with that.