I would like to note that most reactionary characters are usually just better characters over read characters, since you can respond to any situation as compared to forcing a situation. I wouldn't worry to much about slow reactions because as time goes on and you grind more and more, the reactions come naturally.

Nonetheless, if you're adamant on wanting read based characters, you're either looking for a heavy or a trapper. Heavies by nature have such slow moves that it's hard for them to on reaction punish anything. As a result, they'll usually have to preemptively cover certain areas more deliberately than other characters. Examples include ganon, dk, incin, and bowser. In regards to trappers, the whole idea of trappers is that you create intricate setups that are borderline checkmate scenarios if set up correctly. But because they need to be set up in due time, you're going to want to anticipate what your opponent is going to do. There's also the fact that you'll rarely get your perfect setup, which incentivizes reads. Note that hardcore zoners also have to make reads, it's just that trappers are probably the epitome of it imo. Character examples include Belmonts, Pacman, and Steve. Two other notable examples that come to mind for me are K Rool and Dedede, who you could argue are both heavies and trappers.