Here are a few series i created, all of them inspired by my daily life :) 

1) Nail polish series

I have a huge collection of nail polish (that i don't even use :p) so i decided to draw my favorites with a pen. I then added a touch of color with watercolors. No special restrictions for this one. 

2) Chairs from my house

Restrictions : 10 minutes countdown i had to draw every type of chair in my house, even the weird-looking ones :D 

I went from room to room with a piece of paper and a pen; didn't care much about perspective.

3) Digital series : favorite books 

Proof that your drawing skills don't matter -- I sketched super quickly the covers of some of my favorite books, and ta-daaaa : a nice-looking drawing series :) 

Restrictions : no details, just copying each cover and writing down the title author's name