The set 10 Large Simple Jugs is a go-to for fun warm-up problems on vertical through steep walls. They have a nicely rounded lip making them comfortable. Each jug has something a little different to offer in terms of depth and orientation of the incuts.
Several of the holds are hand dependant. For example, some will feel better for the left hand than the right and vice versa, making them an excellent choice to force hand-specific moves when route setting.
A tennis shoe even socked feet, easily stands on this hold.