Validated ideas - List of 5,000 poorly executed but popular apps
Ideas Grab - A list of +3400 ideas that you can get for your projects.
Idea Validator - A customer development tool to help you validate your ideas before building them.
The 25 Days of Ideas - Free resources for coming up with startup ideas
Makerbook - A directory of the best free resources for creatives
Black Blocks - Validate first.