Mockup Photos might be a bit more popular than Unlayer. We know about 1 link to it since March 2021 and only 1 link to Unlayer. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Before that we had some luck using RazorLight, but we did all email templates in an editor Unlayer, exported the html and made a layout and view files. Source: about 1 year ago
They are from ( ublast & Free-mockups & goodmockups & mockup.photos ) and from other websites, those will help you a lot :). Source: about 3 years ago
MJML - The open source framework for responsive emails
Mockup Generator - Create attractive product screenshots with just a few clicks
Stripo - Stripo is an all-in-one email design platform. We enable our clients to build emails of any complexity, including interactive AMP emails, really fast and easy.
shotsnapp - Create beautiful device mockup presentation
BeeFree.io - Bee is MailUp's drag-&-drop editor for responsive design emails.
Simple Mockups - Minimalistic devices mockup pack for Sketch & Photoshop