-
lazysizes
High performance and SEO friendly lazy loader for images (responsive and normal), iframes and more, that detects any visibility changes triggered through user interaction, CSS or JavaScript without configuration.
-
SurveyJS
Open-Source JSON Form Builder to Create Dynamic Forms Right in Your App. With SurveyJS form UI libraries, you can build and style forms in a fully-integrated drag & drop form builder, render them in your JS app, and store form submission data in any backend, inc. PHP, ASP.NET Core, and Node.js.
The effect this has is a bit similar to using skeleton content, and it can do wonders for the perceived performance of your website and help cut on the first contentful paint (FCP) time. With GatsbyJS LQIP comes out-of-the-box with the Gatsby-Image plugin though if you want to use it ouside of Gatsby feel free to check-out lazysizes.