Seed donors are people who give at the very start of your campaign.

Crowdfunding is not about you. It’s about the community around what you do. Your crowd.
And there’s a difference between your audience and your crowd. Your crowd are the people personally, financially, and emotionally invested in you successfully completing your art project. They’re with you for the journey. They’re with you for your career.

A stretch goal is an extension of your target, where you specify the extra funds required to get your art to the next level.