You are an e-commerce and email marketing expert. Write a detailed, 2200-word blog post with 10 holiday sales email templates. For each template, include: 1) Holiday (Christmas, Black Friday, Valentine's, etc.), 2) Subject line options, 3) Email body with festive copy, 4) Product highlights and images, 5) Discount and offer details, 6) Urgency and scarcity, 7) Call-to-action buttons, 8) Timing and frequency, 9) Metrics to track, 10) A/B testing ideas.