How to store information that is not a lead or a company

How to store information that is not a lead or a company

Hello All,
We're new to Zoho CRM. We're migrating from Pipeline, Agile, Act and others. I'm beginning to understand Zoho's metaphor for leads, customers etc. but I'm unclear what to do with companies/contacts who are not customers (or potential customers) but are still vital for the business. These could be industry contacts, vendors, allies, etc. Would love to hear how you all treat these. The thinking on our end is that we would like to be able to link them to leads/opportunities when appropriate. Thoughts?