Admittedly, within this decade alone, I notice KADOKAWA has earned itself as THE Isekai Studio within the anime business.
Prior to KADOKAWA, I did receive the impression that Tatsunoko has a heavy superhero influence, courtesy of its founders, growing up reading American comic books.
Toei and Sunrise are two of the most prolific studios that handle mecha.
Feel free to share your impressions of individual studios.