I was wondering what I should have in my first aid kit for horse and rider when I am at shows?

A first aider should always consider the possible injuries or illnesses that could occur in any scenario. For example if there is a situation where broken bones or dislocated joints can occur then blankets for padding and comfort and slings for immobilisation or support would be handy. If there could be minor bumps or bruises ice packs are good you can buy instant ones that you activate when needed. I must add that anything you use must be in date and approved by the relevant governing bodies. If a patient is going to be in immobile awaiting professional medical attention for a while then weather could be a factor and foil blankets for treatment against hypothermia would be needed. So you must try to consider all the most likely scenarios but prepare for anything. I hope this helps you.