She has provided guest vocals on many other bands' works, most recently on Circa Survive's song "Suitcase" which appears on their latest album "Violent Waves". Previously she took the guest spot on Valencia's latest album, "We All Need A Reason To Believe" on the first single, "Where Did You Go?", Philly/Pittsburgh electro-clash artist Pfunkt's "Anna Log," and Motion City Soundtrack's Even If It Kills Me with one of the tracks being It Had to Be You, Hello Helicopter and Point of Extinction. She also contributes to Reel Big Fish’s live DVD by singing the female parts on She Has A Girlfriend Now. Rachel was also featured as a guest singer on The Wonder Years' song Zombies Are The New Black from their full length Get Stoked On It!, Solo & Chewy: Holdin' It Down from their EP Won't Be Pathetic Forever, and also on the track Hey Thanks from their album The Upsides, as well as on the track Common Weather by Citizen.
- "Powerpop trio deserve more". The Plymouth Evening Herald. 2008-06-21. Retrieved 2010-08-04.
- Work With Valencia