Hello!
So technically the only necessary materials for realistic drawings is paper (preferably sketch paper), charcoal pencils, and erasers.
But if you want to be a little bit more specific, you should get some Q-Tips because it makes the charcoal blend better.
If you want some more detail into the types of paper, erasers, and pencils just use this link! Its great for quality art feedback.
https://thevirtualinstructor.com/blog/10-essential-drawing-materials-and-tools-for-beginners
Let me know if you need anymore help!
Ary~~
