A quick and simple-to-print sponge tray.  There are many other sponge trays out there, many of them quite good.  But you might choose this one because:

• It is big enough to hold multiple sponges
• It has a rack that holds the sponges off the bottom to help them dry easier.  To reduce the chances of mildew, the rack itself only touches the bottom in nine small feet.
• The interior corners are rounded to make cleaning easier
• The rack itself is a simple grid, which also makes it easier to clean.  As much as hex patterns look amazing, they also make it so easy to accumulate mildew.

Print the rack upside down (with the circular feet up in the air).  You may want to print with extra perimeters to help keep the model watertight.

Note that no matter what you do, some mildew will eventually show up; I recommend hand cleaning the tray whenever it gets dirty.

Thank you for reading this, and I'd love to see your print!