Zoho maintains a dedicated Feature Availability and Limits page covering exactly which features are available on which edition, and the specific numeric limits, such as custom fields, workflow rules, validation rules, and storage, that apply to each.
Edition limits in Zoho CRM change more often than you might expect. Storage allowances, custom field caps, export limits, and similar figures have all been revised over the years, sometimes increasing generously (such as Zoho CRM Plus users receiving a one-off boost to feature limits) and sometimes tightened. Any specific numbers we published here would risk going stale the next time Zoho updates them, so the reliable answer is always to check Zoho's own current page directly, rather than trust a static article for exact current figures.