The website is great for drawing surprisingly! It doesn’t have a fill-in bucket, but that’s due to it being infinite probably. If you’re looking for a collab site for doodling with your friends, that’s what you’re looking for! If you have any ideas on what could be added, you can always contact the devs, they usually respond and are super helpful :).
Update: I am happy to edit my review to inform everyone that now Whiteboardfox offers a bucket feature!
It is very good for doodling random ideas! make sure to have fun and keep being creative! It is down sometimes though ;-;
Witeboard - A real-time whiteboard for your team. No signups required.
skribbl - Word guessing based on drawing.
Mural - MURAL is a visual collaboration workspace for modern teams.
LetsDraw.It - Guess and Draw, Drawing Battle, Pictionary, Copy picture - online drawing games where you can compare your skill with others.
Conceptboard - Instant Whiteboards for Teams & Projects
gartic.io - Draw, guess, and win!