Hey! :) I use a Wacom intuous 4 in size medium. It’s never failed me except for the times when the driver malfunctioned, but then I just re downloaded it.
Shiyoon Kim has a brush set that I love so much. Between his set and Kyle Webster’s gouache brushes, I’ve got everything I need. For my newest icon though, I used the dry brush from Shiyoon’s set. And that’s it! I started with flat shapes and added detail with the brush shrunken down a bit.