Below are some helpful anxiety-related resources.
1. Mindfulness aids for parents and children:
Headspace - This is mostly a paid app beyond just a
few basics.
Some expanded content is free, for now.
Another one is Calm
which also has a free trial and then a cost.
Parents may want to use a "mindfulness jar" with their children which they may
have in the form of a glitter jar or can make one as described here.
2. Book and website about anxiety
This is actually my favorite book for parents about anxiety as it has practical suggestions:
Freeing Your Child from Anxiety: Powerful, Practical Solutions to Overcome Your Child's Fears, Worries, and Phobias by T. Chansky
A website with good parent education about anxiety: Worry Wise Kids.