Add Default Opportunity Teams in Lightning Experience

Your reps can add a default opportunity team to opportunities with the click of a single button without leaving Lightning Experience. The opportunity owner or someone above the owner in the hierarchy adds the opportunity owner's default opportunity team by clicking Add Default Team on the opportunity team related list in Lightning Experience, Salesforce Classic, or the Salesforce1 mobile app.
Available in: Enterprise, Performance, Unlimited, and Developer Editions

Each user defines a default opportunity team in their personal settings.

Opportunity Team card with Add Default Team highlighted