Hi {{contact.first-name}},
I hope you're doing well! I came across your website while researching [topic] and was impressed by the quality of your content.
I noticed that you have a fantastic resource page on [topic], and I wanted to suggest an addition that I believe would be valuable to your visitors. I recently published a comprehensive guide on [subtopic], and I think it would be a great fit.
Would you be open to adding a link to my guide on your resource page? I believe it would provide additional value to your audience while also helping to boost both our sites' SEO.
Let me know your thoughts!
Best regards,
[your name]