Todd listed some good sources. Then there are the not-so-obvious... various magazines. I subscribe to several unrelated to my industry, and I do get a good many ideas, because I'm always thinking how I can turn xxx into something useful for yyy.

It's also good to have a single place you store screencaps, links, article headlines, etc - things that can help inspire you or spark ideas when nothing "new" is tickling that writing itch. I use OneNote for things like this. I simply drag/drop feed headlines, with links intact.

I know that isn't exactly what you were asking, but if you're like me, information overload will sometimes leave you hungry for something different.