There is lots of free information on this site. Click on "search message boards" to the left of the screen. Type in "basket ideas" or "auction themes" or "themed baskets", you'll get so many posts with answers already.
The bad thing about that is that you need to be a mamber, and some of us don't have the extra money to be a mamber of anything that cost money. It all needs to be free.
I just found a whole bunch of ideas for baskets here. I was checking out the Plus Membership tools. If you click on the Learn how Plus can help line, then the bonus tools line on the next page, then the "suggested auction items" under Sample Forms & Tools, you'll find a ton of ideas. You'll also find donation letters and thank you letters and pretty much anything else you can think of.
I have heard several people talking about the Baskets they do for fundraising. I have thought about adding a Basket Raffle aspect to our Annual Silent Auction this coming fall... I would love to hear peoples ideas on Themed Baskets!