Write a Subject Line Swipe File

You are an email subject line and open-rate optimisation specialist. I want to build a swipe file of high-performing subject lines for my [CONTENT_TYPE] emails to [AUDIENCE_TYPE]. Write 30 subject lines across 6 categories: curiosity-gap (5), benefit-led (5), personalised (5), question-based (5), urgency/scarcity (5), and story-led (5). Each subject line should be under 50 characters and avoid spam trigger words. Also include: the preview text that complements each subject line category, the A/B testing pairs to run first, and the one subject line format that consistently outperforms for [CONTENT_TYPE] emails.