Tailored sportmans, r.j classics, noble outfitters and kastel Denmark shirts!!!
Check out EMCEE apparel, they have a huge variety in colourful shirts that are very high quality material and breathable. They are around $100 (I think) but are well worth the money. You could also try QJ Riding Wear or Ariat.
Thank you all for your answers! I have a 3 day show coming up and I need an extra shirt for it. I'll look into all of the brands everyone suggested! :)
There are so many brands of show shirts out there! And no, you don't have to spend a lot of money to get a nice one. I really like the kind Noble Outfitters carry. They are supper nice quality, well ventilated, and look flattering on. I recommend you taking a look :)
Tredstep sells great show shirts, they're so comfy but keeps you cool as well