What resources should a beginner collect in The Witcher 3?

The vast world of The Witcher 3 captivates with its colors, uniqueness, and, naturally, monsters! Witchers encounter a wide variety of challenges along the way, and none of them can ever know what they'll need on their journey. Geralt often had to collect odds and ends to craft a necessary potion or even something truly powerful. And how many times have we struggled to find materials for new armor or a sword? Many resources must be found ad hoc. And once the desired item is crafted, we forget about the little things that were so important just a short time ago. But there are certain materials that a decent witcher should collect from the very beginning of their adventures. So, what should a budding Witcher hoard?