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 ;-;
Scribble Online Whiteboard - Scribble Online Whiteboard is an advanced collaborative whiteboard solution that allows you to draw the sketch using the web-based or mobile platforms such as iPad/iPhone and Android.
Witeboard - A real-time whiteboard for your team. No signups required.
Ryeboard - A practical and visual workspace for modern teams
Mural - MURAL is a visual collaboration workspace for modern teams.
Whiteboard Team - Draw, explain and collaborate visually in real-time.
OpenBoard - The OpenBoard software is an interactive white board software.