Thrive Leads is an excellent list-building solution to work with. It includes all types of opt-in form and an extensive selection of conversion-focused templates. Plus you have the additional mobile-specific design options and advanced targeting logic.

Semrush an excellent tool for SEO professionals and pretty much covers all aspects of SEO. Besides backlink analytics, I also like detailed site audit and Ideas features.The interface and feature organization are clear and they've always provided great support