Cubes
A square in 3D! They can be any size, opaque or transparent, a flat color, or textured/decorated.
This is not to be confused with the 6-Sided Die/Dice component. If it has meaningful, differentiated symbols on its 6 faces, it's considered a die, whether or not the game requires rolling it.
This may be a physical item used in a video chat game or a digital representation in the designer's chosen virtual tabletop.