In various Let's Plays, whenever the two are paired together they tend to go by their team name.
Both Michael and Gavin voice characters in RWBY and RWBY Chibi. Michael voices Sun Wukong, a Faunus stowaway who recurring secondary character since Volume 1. Sun ironically has a love affair with Blake Belladonna (voice of Arryn Zech) rather than Ruby Rose (voice of his wife Lindsay Jones), though it might be because Blake is a Faunus like Sun (even though Ruby is also a team leader like Sun). Gavin voices Scarlet David (whose surname is Gavin's middle name), a guest character (and one of Sun's teammates) who appears since Volume 3. Their larger 'Team Nice Kerry' teammate Kerry Shawcross is also of Sun (Michael) and Scarlet (Gavin)'s team, as Neptune.
Michael and Gavin have also collaborated very frequently in other Rooster Teeth projects outside of Achievement Hunter's projects (Play Pals, Lets Watch, Rage Quit, The Off Topic Podcast, Shenanigans, VS, GO! and AHWU). These include (but not limited to) Live action productions (Short comedy films, Sketch comedy skits, commercials, behind the scenes, murder-mystery, sci-if and more) such as Rooster Teeth Shorts, Immersion, Million Dollars, But... Lazer Team and Lazer Team 2, Ten Little Roosters, The Eleven Little Roosters, RT Life, RT Docs (Lets Play Live: The Documentary) in addition to animated cartoons such as RWBY, Red vs. Blue, and X-Ray and Vav, as well as podcasts such as The RT Podcast. This bromance gave them the nickname "Mavin", which ended up being the name of the dual-personality main villain of Eleven Little Roosters.
Ryan Haywood was temporarily a member of Team Nice Dynamite during EXTREME, as he was playing on Michael's account after a previous Let's Play is said to have 'caught up to him' making his own account unusable. Like Michael. Ryan also voices a recurring secondary character in RWBY and RWBY Chibi: Beacon instructor Professor Peter Port, who like Ryan in Minecraft tends to capture native creatures and hold them in various containment structures (though for Port it's for a combination of keeping the innocent populace safe and helping his students - and transfers such as Michael and Gavin's team - train).