Studio 306

Studio 306 is a Canadian audio production studio based in Toronto. They're responsible for recording a couple of original English language productions, as well as occasionally dubbing a few anime (although not as much as The Ocean Group). They're probably most well known for their work on majority of Nelvana's output.
Aside from Nelvana, their other most prolific clients include Decode Entertainment, Guru Studio, Portfolio Entertainment, Cuppa Coffee Studios, Red Rocket Films, Limmock, and Cookie Jar Entertainment among others. Keep in mind that the use of the voice actors in 306's talent pool does not mean 306 had anything to do with the production (for example Breakthrough Entertainment have used the Toronto talent pool extensively, as have the other two major Toronto animation companies 9 Story Media Group and Fresh TV); 306 is just a production company based in Toronto that pulls from the same voice pool the rest of the studios do (it's a very common misconception). All shows listed were recorded in Toronto unless stated otherwise.
A few noted American voice actors actually got their start with work on shows recorded by 306, namely Tara Strong and Cree Summer, who starred in various 80s Canadian cartoons like Inspector Gadget and Hello Kitty's Furry Tale Theater as children long before they were noticed by Hollywood. More recently, Marieve Herington and Katie Crown have joined the ranks of Los Angeles-based voice actors who got their start with them. Additionally, Clé Bennett, Robert Cait, Stephanie Beard and Peter Oldring originally did a lot of work with them as well before they all moved to Hollywood later during their careers. Many former child actors also got their start doing cartoon voiceovers with them, such as Michael Cera and Noah Reid.