Here is my homemade list of initialisms I use frequently:

DCL/DCH = Daily Cycle Low/High
ICL/ICH = Intermediate Cycle Low/High (weekly)
YCL/YCH = Yearly Cycle Low/High
LT/RT = Left/Right Translated
KWL/KWH = Kondratieff Wave Low/High
F = Failed
(S) = Stealth cycle low, i.e. the low was not a confirmed cycle low but price acted afterwards like the low in fact was a cycle low, hence it had to be accepted as a cycle low

BT = BackTest
BO = BreakOut (up/down)
FBO = False BreakOut (up/down)
UL = Undercut Low
OT = OverThrow
ST/LT = Short/Long Term
DB/DT = Double Bottom/Top
RB = Rounded Bottom
H&S = Head & Shoulders
SRZ = Support/Resistance Zone
PM = Precious Metals
PGM = Platinum Group Metals (plat+pall+a few more)
SM = Stock Market
PT/PO = Price Target/Objective
RS = Reverse Symmetry
FS = False Symmetry
PB = PullBack
ATAM = Around The Apex Move
EATAM = End Around The Apex Move
RBK = Rounded Bottom Kickdown
PD/ND = Positive/Negative Divergence
ATH/ATL = All-Time High/Low
MA = Moving Average
EMA = Exponential Moving Average
GSR = Gold vs Silver Ratio
SGR = Silver vs Gold Ratio
TA = Technical Analysis
FA = Fundamental Analysis
CA = Cycles Analysis
SC = Stockcharts
TV = Tradingview
PF = PortFolio