There doesn’t seem to be a topic revolving around System, Technic, or other building classification that isn’t based around Constraction moc, so I decide to devote user personal preference here.
For me, one of my favorite building moc is Jangbricks (even though he departed from constraction building, I personally include him here) mall;
Any MOCs or builders you want to share that doesn’t revolve around Bionicle as much?
Luke Watkins, otherwise known as Derfel Cardan is in my opinion one of the most talented System Castle Builders in the world. His work basically redefined the standard and style of so many castle builders, and you can directly see how his work has influenced so much of the larger Lego Community. He’ll always be a favourite of mine