All "other" expenses, which come in place when owning your horse. :) Those include dewormers (every 2 months), shots (rabies, flu, etc.), teeth floating (once a year), farrier (every 8 weeks). Plus unlimited number of fly mask, fly sprays, ointments, bandages, etc. etc. etc. Lol!
As for feeding and all you have to give more details such as breed/age, what you do with the horse, and so on to get reasonable advices.