"Dog drill" - the adult throws lead passes and the children run one at a time to make a catch. Catching is fun and offers opportunities for success . The adult can adapt throws for different abilities. Children can throw too. Advanced - add a trailing defender on the person running to make the catch harder.
Complete as many passes as you can over a set period of time. Vary distance.
Reactive catching games - throw more challenging throws that could be high, low, wide. The catcher could do 'fast feet' whilst waiting for the throw so they're ready to move and catch.
High catching - two groups of 2-4 players stand opposite each other. A player from one group lofts a high disc to the other group, they practice jumping to catch the disc. The person who catches returns and high throw and so on. Add a points system.
Flutter guts - in pairs or in two small teams standing no more that 5m apart, one players flips the disc to the other team (the disc shouldn't spin like a normal throw). The other team tries to catch the disc. Extension, catch only with one hand. Use points system like tennis or table tennis.
Accuracy - work on hitting targets or getting the disc to land in a target area.
Throw as far as you can - use Javelin throw set-up where everyone throws from behind and line and players race to get their discs once everyone has thrown.
Compass pivoting - vary how wide and in which direction you step to throw. Pivot around the points of the compass and make a throw from each (NE, E, SE = forehand (right-handed player); SW, W, NW = backhand (right-handed player); N, S = either throw).
Ninja throwing - practice throwing from really wide (pivoting) on both sides. Then try throwing from really low and high on both sides.
Curving throws - try to make the disc curve as it flies. Try throwing around static objects with different curves. Aim to curve the disc as it flies but so it still gets to your receiver. What different shapes can the disc make?
Windy throwing - experiment with tilting the different edges of the disc to create different angles and see what the wind does. Throw downwind and see how far it will go *use javelin throwing set-up for safety when windy or focus on shorter throws that will be less affected by wind.
Try setting up a secondary 'jail' activity. If a player drops a disc that they feel they could have caught, they go to jail - they're 'let out' when they've done well at the jail activity.