Drawing

1. #GoldenRatio

   A great Collection of videos on the subject
2. The Human Face and the Golden Ratio
3. Beauty in the Human Face and the Golden Ratio
4. Repose Frontal Mask Application
5. Golden Ratio Beauty Calculator
6. The Math Behind the Beauty

geometry and composition elements

1. The Beautiful People

   there's a slide about surgeon that uses golden section on faces
2. Two-dimensional Geometry and the Golden section

   Mathematical Explanation for root rectangles and the golden section

Books, Links and lists

1. Russell Stutler's Sketchbook Book List

   A great list from a japanese artist

1. Drawing the Human Eye » OnlyPencil Drawing Tutorials
2. 50 Clever Tutorials and Techniques on Traditional Drawing | Smashing Magazine

Building drawing, perspective drawing, scene drawing (like seas, mountains, or trees)

1. Creating Depth in Art and Photography - ZevenDesign

   Very good article
2. The Ultimate Guide to Composition - Part One: Just Say "No"keh | Fstoppers

Any quick sketching hacks, or a speed portrait sketching .. etc

1. Human Anatomy Fundamentals - Envato Tuts+ Design & Illustration Tutorials
2. Cross Hatching Tutorial - With example

Hyper realistic portrait

1. 40 Hyper Realistic Artworks That Are Hard to Believe Aren’t Photographs | Bored Panda
2. 20 phenomenally realistic pencil drawings | Illustration | Creative Bloq
3. 25 Photorealistic Pictures Drawn with a BIC Pen | Bored Panda