It is very important to have the basic materials for start coloring your books or your drawings.
Let's start with the new Adults Coloring Books: You can find the Johanna Basford's Books; The Secret Garden, Enchanted Forest, or very soon the new one; Lost Ocean. These are beautiful books with amazing drawings of special gardens, forests, animals, landscapes and others. Of course, you also can find another books from other authors with Mandalas, Animals, Buildings, Houses, almost anything you want.
Next, we have the Coloring Pencils, you can fin a lot of brands in here, Faber Castell, Maped, Norma, Staedler, but the best for coloring and the ones who professionals use are the Prismacolor Premier, you can find them in a box of 24, 48, 130, 150 and so on. These are very soft core, so they're very soft in use.
Then, the Pens, you can find them in brands like Staedler, Prismacolor and Stabilo, my favorites are the Stabilo 88, they have metallic tip and they're perfect for the small details.
For last, but not least, the markers or Pens with fiber tip, you can find them in Prismacolor, Staedler, Pentel, and Stabilo. I use right now the Staedler Noris, they're not the best but they work for now, the best are the Prismacolor, but the Stabilo 68 are also very good, I'm also gonna use these.