All of it is pretty similar to various pranayama techniques that have existed in the yogas for thousands of years though. Iyengar's Light on Pranayama is a good resource for the various practices [2]. While Wim Hof and Holotropic Breathwork are slightly different, the closest to them from the yogas would maybe be bhastrika pranayam (and here's a random guy on YouTube that comes up when googling it -- just skimming it and it looks basically like what I was taught [3]).
Edit: I realized I didn't answer your question regarding how pranayama/breathwork compares to meditation. It's different than meditation (dhyana or jhana), but it's complimentary and there are elements that are similar. For instance, during pranayama practice you'll often have breath holds/retentions and during that time you'll be instructed to bring your awareness to something (a point on your body, on the awareness itself, etc). This is generally what you'd do in formal meditation practice too, but in this case it's for a much shorter period of time (the length of the breath hold). So in a way it gets you used to working with your awareness, to bring it internal for short periods of time many times. Many people will practice pranayama before beginning formal seated meditation practice. I personally use nadi shodhana before meditation practice, and more vigorous pranayamas like kapalbhati and bhastrika before/during/after asana practice. They're also good to do in the middle of the day when you need a bit of a reset.
[1] https://www.youtube.com/watch?v=tybOi4hjZFQ
[2] https://archive.org/details/iyengar-bks-light-on-pranayama-o...