While not considered a school of Magic, Ritual Magic can be it’s own specialty. Ritual masters are key to successful rituals and is one area where experts who otherwise don’t have a lot of power on their own can leverage skill over raw power to massive effect.
Ritual Magic is all about sharing the collective power of a group and then the key position working with that magic and directing it into it’s final effect. This can make a small group of Journeymen able to rival an Adept for the amount of raw magic they can field. With a capable and experienced Ritual Master they could likely win a fight.
On the other hand most Adepts don’t tend to like performing Rituals. With access to around the same amount of power from some Ley Line Nodes they aren’t bound by the same limits as others. Adepts often get big heads and can be hard to work with often being described as ‘herding cats’. This makes it much harder for them to work in sync like rituals require as well. Some consider this unfortunate as it’s likely High Magic would require Rituals involving multiple Adepts.