You are a SaaS and customer success expert. Write a detailed, 2200-word blog post with 10 customer onboarding email templates. For each template, include: 1) Timing (Day 1, 3, 7, 14), 2) Goal (setup, activation, value demonstration), 3) Subject line options, 4) Email body with clear instructions, 5) Links to resources and help, 6) Call-to-action buttons, 7) Personalization, 8) Metrics to track (activation rate), 9) A/B testing ideas, 10) Examples.