Yes, this is a thing. Yes there is a lot. Most of these are featured in the Markiplier TV video, but I included a few extras! I tried to go by lyric. Credits to the artist (I can't read the name in the corner, lemme know if it's yours!)

Markiplier- Hey Look Ma, I Made It

"Hey look Ma, I made it; Everything's comin' up aces, aces; If it's a dream, don't wake me, don't wake me..."

Wilford Warfstache- Nine in the Afternoon

"You could 'cause you can so you do; We're feeling so good; Just the way that we do; When it's nine in the afternoon..."

Darkiplier- Nicotine

"I taste you on my lips and I can't get rid of you; So I say d**n your kiss and the awful things you do; Yeah, you're worse than nicotine, nicotine..."

GOOGLEplier- Crazy=Genius

"If crazy equals genius; Then I'm a f**king arsonist; I'm a rocket scientist..."

Dr. Iplier- Nails for Breakfast, Tacks for Snacks

"To offset the pills; You know you should take; It a day at a time; The hospice is; A relaxing weekend getaway..."

Ed Edgar- Camisado

"Just sit back, just sit back; Just sit back and relax..."

Bim Trimmer- Mad As Rabbits

"Now he drags down miles in America; Briefcase in hand.; The stove is creeping up his spine again; Can't get enough trash..."

"The Host"- Miss Jackson

"No one knows it's you, Miss Jackson; Found another victim; But no one's gonna find Miss Jackson, Jackson, Jackson..."

King of the Squirrels- I Write Sins Not Tragedies

"Well, this calls for a toast,; So, pour the champagne, pour the champagne!...; I chime in with a..."

Jim/Jim- London Beckoned Songs Written About Money By Machines

"Make us it, make us hip, make a scene; Or shrug us off your shoulders; Don't approve a single word that we wrote..."

Yandereplier- Girl That You Love

"Drop every pretense; Drown every sense you own; For the girl that you love..."

I feel like KOTS's would have been better if it was "I chimed in with a 'I'm King of the Squirrels!'" But you know, gotta keep it accurate