Leoric’s Shinbone in the fireplace at Leoric’s Manor, also in Act 1.

The Black Mushroom in Tristram Cathedral in Act 1.

You can farm for these materials in Story or Adventure Mode, and Adventure Mode might be easier because it won’t require you to restart a questline to reset a map. None of these are guaranteed drops - sometimes the items drop from an elite like Chiltara and if it doesn’t spawn you’ll need to reset the entire map to try again, or the item simply won’t be present and you’ll have to reload the quest or map to get another chance for it to spawn. The Staff of Herding is not something you can just go to the Blacksmith and craft, although you will need him to make it - it requires notable finds from throughout Sanctuary, some of which you will need to farm for to pick up. In order to reach this magical land of treasure and rioting pantone swatches and teddy bears (seriously) you have to assemble the Staff of Herding, But the developers decided to continue a tradition from Diablo 2, namely the Secret Cow Level, and this time take the opportunity to poke a little fun at those players who felt like the game was too bright and colorful. Now, I have no idea what they’re talking about - Diablo 3 is not, in my estimation, a particularly bright or colorful game for the most part. When Diablo 3 was in development, some players were less that enthusiastic with what they saw as a garish, more brightly colored game than its predecessor. The more complicated answer is because people simply couldn’t calm down about Diablo 3‘s color palette. The simplest answer is because the developers of Diablo 3 love you very much. Now, adventurer, let me prepare you for the lands of Whimsyshire and Whimsydale.

Just because the residents are as polychromatic as the land they inhabit, it doesn’t follow that they aren’t dangerous. These places are brightly colored and magical - you could easily get lost in their twisting paths through rainbow arches and smiling clouds, but be warned. These magical places, denied by some, are accessible through strange portals, but despite their similarities there are some differences between the two.

Yes, there’s not just one, but two lands full of ponies and stuffed animals and rainbows in Diablo 3.

Mysterious cave diablo 3 liquid rainbow