I have seen many Hanoverians and Holsteiners in eventing.
Depends on how high you wanna go in cross country. But pretty much any horse that has the physical ability to jump I think has potential. I look atbreed too but I also just look at how they are built and all.
You could find a nice let’s say quarter horse and a crappy warmblood. So idk The whole breed thing is just eh. Idc what breed my horse is as long as he or she can do it. So yeah!
But I will say majority of the time warmbloods are known for being the nicer ones for jumping.
Warmbloods are quite good as well as Welsh and breeds similar also cons can be quite good too
Hope this helps