Help Needed: Finding TAM for B2B Greeting Card Publishers in the UK

Hey Clay experts. I’m having a lot of struggles with finding my TAM and sorting out unqualified leads to build a precise list. We have a really niched down audience and i’ve spent a lot of time and credits on trying to sort out the list. Someone interested in testing their skills on this? Target: B2B/Wholesale Greeting card publishers in the UK. They’re hidden under several different categories and industries like: