Here is a list I found..... maybe others can add to it.
Ams= Ameraucanas
BA=Black Australorp
BB=Buff Brahma
BBR=Black Breasted Red
(BBS= Blue, Black, Splash)
BCM = Black Copper Marans
BF=Bantam Fowl
BfAms= Buff Ameraucana
BlAms= Blue Ameraucanas
BkAms= Black Ameraucanas
BLRW=Blue Laced Red Wyandotte
BO= Buff Orpington
BR= Barred Rock
BRAms=Brown Red Ameraucanas
BSL = Black Sex Link
BSM=Blue Splash Marans
BTB=Black tailed buff (usually Japanese bantams)
BTW=Black tailed white (usually Japanese bantams)
BWA= Blue Wheaten Ameraucana
CM=Cukoo Marans
CW=Columbian Wyandotte
Cx = Cornish Cross
Del=Delaware
DB=Dark Brahma
DBH=Delaware Blue hen
EE = Easter Egger
FBCM=French Black Copper Marans
GDW=Golden Duck Wing
GLW=Gold laced Wyandotte
GPH=Gold Penciled Hamburg
GSL=Gold Sex Link
JG=Jersey Giant
LB=Light Brahma
LS=Light Sussex
(LF=Large Fowl)
NH=New Hampshire
NN=Naked Neck
OEE=Olive Easter Egger
OE=Old English
OEG=Old English game (usually standards).
OEGB=Old English Game Bird
RIR=Rhode Island Red
RSL=Red Sex Link
SDW=Silver Duck Wing
SF=Salmon Faverolle
SlAms= Silver Ameraucanas
SLW=Silver Laced Wyandotte
SpAms= Splash Ameraucanas
SPPR = Silver Penciled Plymouth Rock
SS=Speckled Sussex
SSH=Silver Spangled Hamburg
WAms= White Ameraucanas
WCBP=White Crested Black Polish
WCP=White crested polish
WFBS= White Faced Black Splanis
WhA= Wheaten Ameraucana