Buyers don't want to be contacted by random people, by phone or email, and generally don't make this information available online. You would have to contact each company through their web sites, and ask if they accept blind submissions from vendors, and how and where to submit your products.
Some companies have an open buyer day, where you come in, and show your stuff in person. I worked for a craft retailer that generally did this once a month.
You can also participate in trade shows to get your work seen, or work with a distributor, who will show your work.