You are a customer experience and email marketing expert. Write a detailed, 2000-word blog post with 10 NPS survey email templates. For each template, include: 1) Timing (post-purchase, post-support, periodic), 2) Subject line options, 3) Email body with clear ask, 4) NPS scale and question, 5) Follow-up for promoters and detractors, 6) Call-to-action buttons, 7) Personalization, 8) Metrics to track (response rate, NPS score), 9) A/B testing ideas, 10) Examples.