You could survey your customers and see what products or services they would like you to offer in the future. Spy on your competition and see what products and services they're offering or not offering. If you would like to, bundle unrelated products or services together, ask your customers which ones would be of interest to them. Bundling can also increase your target markets which in return would give you a larger audience to sell your products and services. You're now targeting people who want the baseball magazine and those that want to play baseball out in the yard.
Some people buy a package deal just to get one of the products.
There are many sources where you can find products and services to create a package deal. You can buy them from wholesalers or drop shippers. Team-up with your competition to create a package deal. You could joint venture or cross promotion deal with other businesses. You could also create your own products and services.