OptinMonster - OptinMonster helps to convert abandoning website visitors into subscribers and customers.
Unbounce - Unbounce lets marketers and businesses build, publish and test landing pages without IT or software. AI enhanved A/B testing and lead gen make it a powerful marketing tool.
Subbscribe - Opt-in form to help you grow your web subscriptions
LeadPages - LeadPages™ Software is the world's easiest landing page generator. It's the easiest way to build conversion optimized & mobile responsive landing pages.
Monarch - Social media sharing plugin for WordPress
Twik - Twik automatically personalizes websites to increase conversions.