The mods are slowly trickling in, with mostly cosmetic at this time. Otherwise since Kia and Hyundai share a lot of components it's mainly trial and error to see what existing parts will fit the new Forte. Examples are the Elantra AD having the same suspension (I'm using a set of Eibachs made for the Elantra) and the K&N panel filter for the Veloster which fits the 2019+ Cerato/2020+ Forte.
I'm sure the cold air intake will be the same.Exhausts should be available soon, but you can always get a 2.5" custom setup made. I haven't found anyone that tunes the new Forte yet, but did find a company called DTE Systems that has a piggyback system for increased power and torque.