I was wondering if a modmaker could make a mod where there is a symbol next to a horse you've bred. I do breed a lot of foals and it would be nice in the game if I am going through races a horse not owned by me (but was bred by me) has a symbol (maybe an H? bubble) like a graded race one.

If before you sell the horse you open up the notes section and add a note: It can be anything even "xxx", then the horse will forever show up on the racecard with the little white triangle/arrow.