Kate Beddow is a great person to follow and she has produced some great lessons based on the Pixar film Inside Out.
There are also some other lovely ideas on this Pinterest page linking the film with mindfulness
At my school we use an amazing resource called 'Focused for Learning', written by Kelly Green in the Gloucestershire Healthy Living and Learning team. It is well worth investigating if you would like to introduce mindfulness into your class.
Facebook is another create source of inspiration and here are a couple of pages I follow providing some useful information.