Nothing wild here, but a slight take off on your “Show the Ball” drill that worked well with my team was incorporating it into a game of “Statue”.
Statue Throwing Drill
When you call out “Statue”, all of the kids are supposed to become statues in the throwing position with the proper grip. Because they are “frozen”, it allows coaches an opportunity to check grips and body form carefully.
As you are checking for these things, the game for the coach is to try and make the player laugh (making funny faces, saying funny things, etc.) and become a “non-statue”, one player at a time, spending 10-15 seconds trying to make each kid laugh.
The best “statue” wins that round. The kids love the aspect of trying not to laugh, and the “freeze frame” gives the coach enough peace to note what aspects need work. Several rounds in a row are easily workable.