IE
One good feature of the newer IE dev tools i like is that I can make the browser emulate lower versions of IE, so I just need the one VM to test back to where we start supporting (Ideally I'd not open IE at all but at least this little detail makes it somewhat less cumbersome to test for)
modern.ie supplies VMs to test on which is pretty cool, so it looks like they're trying to help testing, just not with anything particularly powerful or exciting (or with a decent browser)