Microsoft has actually a website which may be handy for many web developers to design their pages cross platform, yes we know it is amazing, it is no secret we are not a big fan of their IE browsers but they are still very popular especially in big corporations ; but this site really may help you make your websites better compatible with different browsers hence it deserves a spot on our [Resources] blog.
A few options modern.IE providers on the website:
modern.IE will help you finding virtual machines to check your websites.
test several browsers through BrowserStack.
Run a compatibility check directly from the site with many cool tips and tricks.
Scan for common coding progblems.
Read articles about legacy browser compatibility.