Depends on who I am working with and what they know, sometimes they are pre-gamed but I have seen
- "Bull horns" facing each other to show we're shooting 1-and-1 on both ends
- Sticking out a fist to show the next dead ball will be a media timeout
- Point to wrist or in the air to show time is about to expire or there is 1 minute left, again depends on who I'm working with
- Hold fingers showing about an inch to mean the shot clock is low during a dead ball
- Running hand back and forth to indicate the player inbounding the ball may run along the baseline, also point to the spot to indicate a spot thrown in