Here are some of the resources that I worked through as study material for the VCAP6-Design exam. A lot of these links and the discovery of these links can be attributed to a lot of others, and I'll try to credit them where I can.
vBrownBag EMEA - VCAP6-DCV Design - vBrownBag YouTube channel Some great presenters here that highlight some of the key concepts and follow up with discussions vThing - VCAP Study Resources - Andres Herceg's blog https://vthing.
After months of studying and a Design and Deploy course for good measure, I passed the incredible VCAP6-DCV Design exam!
This certification in combination with my VCAP5-DCA from 18 months ago has awarded me the VCIX6 title which I'm incredibly proud of. Here's the official link from VMware about the certification: https://mylearn.vmware.com/mgrReg/plan.cfm?plan=89125&ui=www_cert
To give you an idea of what the Design exam is about, take a look at www.virtualtiers.net. That exam simulator is a great representation of how the exam is formatted and how you're tested.