For your country themed bridal shower, you can purchase western cowboy hats, western whirls, country themed cutouts, "red-neck" street signs, rusty barbed wire garlands, and country themed napkins.
For baby shower favors you can get a lot of ideas from beau cou and also order some decently priced favors from their website. They have everything from boy to girl themed to even neutral in case the gender is unknown.
Precious Moments features a large amount of products made for baby showers, children's party's, adult party's, baptisms, and favors. They offer products such as themed party plates, paper lanterns, baby shower gag gifts, and bridal shower candy.
Rubber duckies would be a must, you can plan party games with them. At the party city web site (http://www.partycity.com) you can find a wide variety of duck themed supplies such as banners, table clothes and favors.
A popular place to buy Christmas themed shower curtains is online at BedBathStore. Other sites that sell Christmas themed shower curtains are Amazon, CafePress and PopularHomeCollections.
For a duck themed baby shower you could have a cake or cupcakes in the shape of a duck, play pin the bill on the duck instead of pin the tail on the donkey and you could give away small rubber duckies as favors or prizes.
Party favors for a casino themed party can be purchased from many places online. Party City is an excellent store to shop for party favors, and its online branch is just as good. Amazon is another great place to look.
Bed Bath and Beyond sells personalized favor bags, generally bridal themed. http://invitations.bedbathandbeyond.com/Personalized-Favors/index.cat Personalized gift bags are available from other retailers online, such as welcomebags.com and partybasics.com.
Any local party supply store will sell inexpensive "over the hill" themed party favors. Party City and Oriental Trading Co. are great places to start your search.
Some neat bachelor party favors are adult themed items. Spencers is a great place to find bachelor party favors, or online. A few examples of good favors are: magnets, "grow a lover" favors, and T-shirts.
Duck themed baby shower is great for a baby shower. Duck is a gender-neutral theme that works for both boys and girls. http://www.newbornbib.com/top-menu/articles/throw-a-baby-duck-themed-baby-shower/
You can get baby boy themed shower invites on the sites Tiny Prints, Wishing Tree Designs and Vista Print. Each site has dozens to choose from and customize.
There are many beach themed shower invitations available on Minted and Wedding Paper Divas. Vista Print also has beach themed shower invitations on their site. All of these options have templates so you can customize your invitation to suit your needs.