Not really concept work but here's some of my dead old 2D artwork (over 8 years ago, the A-level stuff at the bottom is over 12 years old! gulp).
The only computer-based ones are the Dunction Wood pictures, the rest are pencil, charcoal, acrylic or oil.
The newer stuff (general and life drawing sections) are when I decided to start up again last year and learn about proper proportions of the body. I've got more but its hard to scan A1/A2 sized sheets

https://www.flash-fx.net/2D/