Believe it or not, there are 198 active scuba certification agencies! Some only do tech or cave, but most aren't limiting themselves. Also many colleges/universities offer scuba as a class. I'm not sure if the colleges give you a card from one of those private companies or not. I understand a college scuba class is much more in depth than a typical private scuba class but I've never personally done it.Diving is probably one of the very few activities that’s not government regulated, where the majority of participants willingly agree to pay 2-3 privately owned corporations for training where it’s not in fact required. As a matter of fact, I can’t think of another one.
The thing is that it's not regulated. That means I could start "kelemvor scuba agency" and offer cards to whoever I wanted based on whatever criteria I wanted today and it would all be legal. Now, if some boat had actually heard of kelemvor scuba and decided not to accept my certification they could do that. Most boat ops would not notice. Technically, my card would be as good as any other companies' card... and if I got some crossover instructors to issue my cards the training may very well be good training.