mabey just basic horsemanship and trust
If you have hills, hill work is great for strengthening your horse. It helps them get stronger.
Bathing, cuddles, kisses, treats, free lunging
Check out the 7 games of parelli. Great ways to continue bond with your hor
look into clicker training!
If you are there every day, maybe you can try new disciplines with your horse. Maybe take him for some ride out if you can.
You can also do some ground work with him taking him out handwalking to eat some grass ...