101 Jumping Exercises by Linda L Allen has lots of ground pole exercises that are the foundation for good control over fences. Has lots of jump exercises too as you progress.
101 Dressage Exercises For Horse & Rider by Jec Aristotle Ballou has lots of great flat work ideas.
Love them both! Mix and match for all my horses when I encounter issues or just need to liven up the dull winter months without actually jumping much. they are great for ideas when you're not working regularly with a trainer too.