Whey wrote I've seen so many through my job. I won't even be able to remember them all but here's some:

Missy Elliot
50 cent (G unit)
A-Ha
Adele
Professor green
Mumford and sons
Taylor swift
Jess Glynne
Ellie Goulding
Jason Derulo
Madonna
The Courteeners
Def leopard and Whitesnake
The darkness
Skepta (boy better know)
Imagine dragons
Duran Duran
Fall out boy
One direction
Union J
ASAP Rocky and Wiz Khalifa
John legend
Maroon 5

& lots more !
That's just in regards to music. Seen live including non musical I have seen:

Dynamo
Frankie Boyle
Michael McIntyre
All wrestlers including big show, Kane, the undertaker etc.
& much more

Perks of the job I suppose