What should i sketch?

Ok this is the 3rd time i've asked this but what should i draw? i have no clue, and i just finished a drawing of a koala i've been working on since march. i need some ideas but i don't want to draw any animals, what i see out my window, and i cant draw people, (i can draw things like hands or something like that but not portraits) or eyes or the sky, i also dont want people telling me to draw what i want to draw cuz i dont know! just so you know some ideas of what lately of done.... here are the drawings or paintings i've done recently: i drew 2 hands making a heart, a hand holding a glass bottle, koala, 3 giraffes in neon colors which i later on painted. and i do kinda want a challenge or something that i can work on for a while, not something i am finished with in like 10 minutes. Sorry i'm so picky with what im asking for, but all answers are appreciated! :]