Maybe you're shining your online look, or cooking up some bookmarks to hand out as author SWAG. Get ready to pounce!
With a spice rack of icons and a little technical flourish, you can create a flavor that's distinctly you (or your muse/pseudonym/public mask). Here are a few sites I have found helpful.
Now isn't the time to go into the technical aspects of downloading and using a design program like GIMP or Scribus. But, I do want to dwell on the questions of copyright for a moment (in a I'm-not-offering-you-legal-advice-right-now kind of way; consult a lawyer for that). Remember to offer thanks and/or money to the creatives!
There tend to be three main categories on sites like these. You'll find premium icons where you need a subscription or a one-time payment to use the icons. Some icons are offered with a creative commons license (e.g., CC3) where you can use it as long as you tell people where you got it. Occasionally you find the ones that are just plain free for any use (public domain, CC0).
And as a bonus for reaching the end, here's a 1/8th-baked idea for the card game Space Alligators. The background comes from Pattern Cooler (and also NASA for the swirls of Jupiter).