This is a hard question to answer as it's too broad. I would say it depends on what corals you are trying to propagate. Each coral is unqiue and different. Some are far eaiser than others.
Meaning some anyone could propagate. While there are some that haven't been done successfully yet. Still others that people attempt but there are low success rates.
Also dbtc is a great way to get easy to propagate coral. I would recommend trying leathers, or zoas as the easiest to grow out and frag.
If you have a specific type in mind mention it that you could get feedback that's directed towards a specific type.
Some people do actively propagate I do with leathers and I have with mushrooms. I've seen videos of people doing it to expensive scolymia corals. (Most probably wouldn’t dream of taki g the chance of cutting such an expensive coral) others like nems can be cut in a way to make more. Yet feeding them directly can also make them split faster.
Beyond leathers or common type mushrooms or sps, I lean towards the natural method of letting them grow out.
