J.T.
My sister did a rubber duckie theme for me.... duckie cake, small, clear bowls of water tinted blue with a single (or more if the table was bigger) duckie swimming in it. She bought molds to make pink, white and blue chocolate/candy suckers for favors..... Duckie stuff is easy to find at Oriental Trading Co.,dollar stores, floral supply stores, etc. so it was very cute and not hard to find all the materials.
And my Aunt hosted a shower for me as well - with the 'a baby is blooming' theme. Favors were small, clay pots - she wrapped the lip with ribbon and had little seed packets in each that had a little poem (with an Anne Geddes type photo) about the seeds growing like the baby (if you decide to go that way, shoot me a personal message and I can send it to you). Centerpieces were tiny planters and watering cans (should all be on sale now at Target, etc.) with flowers. Oh.... and she made the invites too, with an image matching that on the favors. Again, adorable :)
Either way, consider piling up the favors on cake stands in the center or gathering them somehow in the center so they serve as both decor and favor. It will work well if you don't have lots of space on the tables and is a time and money saver!