Product Market Fit
Send this to users who have been active for a few weeks to measure product-market fit. It asks one question, how they would feel if they could no longer use your product, with three one-click answers and a short note from the founder. Link each answer to your survey and send it only to people who have used the product enough to judge.
Loops
Survey people who know the product
Build the audience from usage, such as contacts who signed up a few weeks ago and used the product recently, so the answers come from people who can judge it. Give each answer button its own link to your survey form, and send from a real founder name so replies reach someone who reads them. The survey examples show other formats.