Types worth the effort
Organization, Product, Article, FAQPage, BreadcrumbList, LocalBusiness, and SoftwareApplication. That's the shortlist. Everything else is niche.
Validation over volume
One perfectly implemented Product schema beats 14 half-broken ones. Use Google's Rich Results Test and fix warnings — they become errors within a release cycle.
The review trap
AggregateRating schema without genuine reviews is a manual penalty waiting to happen. Don't fake review counts, ever.