This is a list of 99% of the undercover agents..i've used it for a while and never had a problem with it. hope it helps you all and please do add any that you dont find on the list :)

A Der MAASTER
aaa
Adem
aGGro
Agoraphobic
Agro
Al Mimose
Alex
Always
Always am Boden
Ansgar
Appe Roll
Azad
--------------------------------
Barzie
Bazen
Bernd Schimmel
Big
big ease
Big Eye
Big Eze
Big Pavlo
Big Podex
Big Shore
bitches
Black
Bladelive
bomb bomb
Boogi John
Boonbreaker
Brodiacles
Bruno
--------------------------------
CannaBon
CannaBong
CarloCoxXNuTTeN
Cequewara
Che Bastian de la Serna
chemiker
Chemiker der Dealer der weibliche
Chiller
Chronik
Ciffer
Clemshe
CleMsHe thE KiLlEr
Coffeeshop the dealer
comander
cOre
Crackalack BK
cyberssssnake
--------------------------------
dA reAl gAngstA
Dahood
danny
Dany
daywalker Pussy
Dealer master
dealermaster
Der Maasta
DER MC DREW
Der Mc Drum
Der mit der Wiener
Der Penis
DerDon
Die Dorle
Die fiese Schlange
Die Gark Gang
DieDorle
ditschi tha smoka
djeda
DNap
dobblet
Doblet
Dobletder
don drogerio
Don-Marvino
Don Manni
Don Penis
Don Rio
DonDrogerio
Dorgen ExPeRtE
Drachenblut
Drgen King
Drink
drink and drive
Drogen ExPeRtE
Drogen Jukys
Drogen Junkys
Drogen King nr one
Drogendealer pro
Drogenflash
drugman
DruGMaN da DealA
DruGMaNda DealA
--------------------------------
eesha
Eestha
EIZTARZ
Elvis
ElZtArZ
Erazer
Erwin Anuslecker
--------------------------------
farid
Faruk
faruk erus
Fat Bastard
FatBastard
Feanarths bester Freund
Francesco
Freaky
Fredson
Fredson
FUCK YOU
fuxxxz
--------------------------------
Gangsta - Hamsta
Gangsta-Hamsta
ganjamnffin
ganjamuffin
Gansta-Hamsta
Georg
George
G-EDDI
G-Junes
gohstpit
gruenemamba
GTI - Driver
GTi Heinni
GTI-Driver
Gweni
G-ZUS
--------------------------------
Haschtier
Heabanger
HeAd BaNgEr
Headbanger
HELGINHO
Hobbysniffer
hoden
Holli1703
Houdl
Hwoelpl
--------------------------------
Ich mal wieder
Infernalos
Inwoelpl
Isan
Ivan Vasili Popov
Izmir
--------------------------------
Jack
Jake
Jake the
Jake The der Dealer
Janus
jealous
Jenny
Jet force psycho
Jimmy
JOE CRACK THE DON
JOE DRACK THE DON
Joerg
joerg baumann
JoergBaumann
johnnie koks
jonni
Jonny
Jooni
Joonny
Joseph
Juni
Junkeey
Junky
Jürgen Klinsmann
--------------------------------
Kanonnendonner
Kates
Katlina
Kiddou
Kiffer stone
Kifferwax
Kill Bill
KillA
KillerII
king hupe
Kings of the Hill
Kool
Krautbauer
--------------------------------
Lady Bitch
Landser
LeDiviorce
Lennart
Lev Town
LevTownDealer
Long Don Silver
LucIfer
LunisGardness
--------------------------------
Maddin
Madfox
Maerkelinho
Mafiabss
MaLaGa
Marco
Marios
marmin
Massino
Massion
Master
Master der Dealer
Master ms
MasterDeal
masterdeluxe
Matze
MC Druf
M-Cz
Methylsalicylat
meydinho
Mickler
Mika-Mg
Mike
Minchia collce
Minchia Cooker
mishamann
mishamaus
Moltesanti
Moltisanti
Monn
Monn the Dealer
MOoni
MoRroc
--------------------------------
Nazi
Nebuschtan
Neisch
Nic geos surf
Nic goes surf
nice
NooB
--------------------------------
Okki
Omma
Otze
--------------------------------
Pauerheads
PaulWall
Paver
Paverheas
Phillipsmatrix
Phoenix
PornoPaddy
Proditor
Prollkind
Psycho
-psycho-
--------------------------------
Raganov
Rapidla
RastaGyver
Ratiopharm
Razer
Rock Ron
Rocky
Roflrofl
Roganov
Rolex
RoLLeX
Rudelführer
--------------------------------
Salvatore
SaNdScHi oR JuSt GoD
Satan
Shane der
Shingo
Shylar
Smaile
Smoker King
Staaken
Stahlrose
Stopi
STRYKA
StRyKeR
--------------------------------
tahagona
tahagona
Tchort
Terroa
Terrorkueken
Teufelsweib
the Gark Gang
The Ripper
The Shadow
The-Ripper
theShadow
Tobbi
Tobi Tuker
TobiTobsen
TomErik
Tonny Montana
tooradical
Tribbel
TWISTA
--------------------------------
Udo
uwe
UMMI
--------------------------------
Vedder
Veder
--------------------------------
waldi
Warrior King
WorriorKing
--------------------------------
X to the Z
xFrank
x-Frank
x-treme
xxbootxx
--------------------------------
Zack

UMMI is a undercover agent

thnx just updated it in the main list :)

Coffeeshop the dealer is a undercover agent

Woelfi is a bloody copper

ghostpit is a UC you had it misspelled in the list.

Lev Town Dealer

Lady-Bitch the dealer is a undercover agent
dermitderWiener the dealer is a undercover agent
DonDrogerio the dealer is a undercover agent
Tonny Montana the dealer is a undercover agent
LunisGardness the dealer is a undercover agent
hwoelpl the dealer is a undercover agent
Moltisanti the dealer is a undercover agent
Headbanger the dealer is a undercover agent
xxbootxx the dealer is a undercover agent
Dorgen ExPeRtE the dealer is a undercover agent
chronik the dealer is a undercover agent

MizZ-Bonny

mynigga the dealer
Lady-Bitch the dealer is a undercover agent
dermitderWiener the dealer is a undercover agent
DonDrogerio the dealer is a undercover agent
Tonny Montana the dealer is a undercover agent
LunisGardness the dealer is a undercover agent
hwoelpl the dealer is a undercover agent
Moltisanti the dealer is a undercover agent
Headbanger the dealer is a undercover agent
xxbootxx the dealer is a undercover agent
Dorgen ExPeRtE the dealer is a undercover agent
chronik the dealer is a undercover agent
Ceguewara
Drachenbrut
tahagona
Matze
Djeda
Che Bastian de la Serna
Ich mal wieder
Fredson
Paverheas
Kiffer stone
Tchort
MaLaGa
Stahlrose
CleMSHe ThE KiLlEr
xFranK
Shylar
drogen king nr one
JakeThe
WorriorKing
Drogenflash
dA reAl gAngstA
Junkeey
Zack
Omma
Izmir
Feanarths bester Freund
aGGrO
Kiddou
bomb bomb
Die fiese Schlange
dahood
big
Adem
Elvis
Comander
azad
Ciffer
Jet force psycho
RAZER
kifferwax
Vedder
Crackalack BK
StRyKa
Master
teufelsweib
George
Boogi John
Erwin Anuslecker
chronik
BladeLive
Mike
theShadow
xxbootxx
Lev Town Dealer the dealer is a undercover agent
Junkeey the dealer is a undercover agent
kifferwax the dealer is a undercover agent
G-Junes the dealer is a undercover agent
Shane the dealer is a undercover agent
dahood the dealer is a undercover agent
StRyKa the dealer is a undercover agent
big eze der Dealer is a undercover agent
aGGrO the dealer is a undercover agent
dA reAl gAngstA the dealer is a undercover agent
Headbanger the dealer is a undercover agent
Bruno the dealer is a undercover agent

Lion
Marious
lurchi
McMash
xy-bande
Afrob
cCcBZKURTcCc
JOKE
aerkelinho
DiamantK
EraZeR
der Gangster
big pavlo
Brodiacles
LeDeviorce
LunisGardness
MinchiaCooker
Graves
KillA
Fredson
M-Cz
dealer master
Headbanger
DruGMaN
Ratiopharm
Dobblet
dA reAl gAngstA
Alex
Lev Town
Adem
Shane
GTi Driver
CannaBong
RudelFuehrer
JOKE
X to the Z
Don Penis
Isan
ApE RoLL
DonDrogerio
Chemiker
X X X X staaken
rudelFuehrer
Izmir the dealer is a undercover agent
Lev Town Dealer the dealer is a undercover agent
Junkeey the dealer is a undercover agent
kifferwax the dealer is a undercover agent
G-Junes the dealer is a undercover agent
Shane the dealer is a undercover agent
dahood the dealer is a undercover agent
StRyKa the dealer is a undercover agent
big eze der Dealer is a undercover agent
aGGrO the dealer is a undercover agent
dA reAl gAngstA the dealer is a undercover agent
Headbanger the dealer is a undercover agent
Bruno the dealer is a undercover agent
Lady-Bitch the dealer is a undercover agent
Master MS the dealer is a undercover agent
ganjamuffin the dealer is a undercover agent
dermitderWiener the dealer is a undercover agent
DonDrogerio the dealer is a undercover agent
Tonny Montana the dealer is a undercover agent
LunisGardness the dealer is a undercover agent
hwoelpl the dealer is a undercover agent
Moltisanti the dealer is a undercover agent
Headbanger the dealer is a undercover agent
xxbootxx the dealer is a undercover agent
Dorgen ExPeRtE the dealer is a undercover agent
chronik the dealer is a undercover agent
dealer master the dealer is a undercover
bomb bomb the dealer is a undercover agent
Phoenix the dealer is a undercover agent
Mike the dealer is a undercover agent
Kiddou the dealer is a undercover agent
xy-bande the dealer is a undercover agent
Don ka

SonicBrew is a copper!
benny

El Diablo is a copper

The Gark Gang
BlasterMaster


Will update as I find more!