I noticed a thread like this on the SQ forum which was originally started by Kiwi Flyer, and thought what's good enough for SQ is good enough for TG.

How many destinations / routes have you flown on TG? The following is a list I compiled of all possible TG routes/destinations. Please feel free to add/correct any mistakes in current or previous TG (non-codeshare) destinations/routes. I'm sure I'm unaware of a lot of discontinued routes from the past. I've considered BKK at the old site (Don Muang) and at the new site (Suvarnabhumi) to be the same airport if flown when the same BKK code was used. If flying into/out of Don Muang when the DMK code was active, I consider it a different airport from BKK.

Current international TG destinations from BKK
AKL
ARN
ATH
BLR
BNE
BOM
CAN
CCU
CDG
CGK
CMB
CPH
CTU
DAC
DEL
DME
DPS
DXB
FCO
FRA
FUK
GAY (seasonal)
HAN
HKG
HYD
ICN (nonstop, 2 routes with stop)
ISB
KHI
KIX (nonstop and with stop)
KMG
KTM
KUL
KWI
LAX
LHE
LHR
MAA
MAD
MCT (no nonstop)
MEL
MNL
MUC
MXP
NGO
NRT
OSL
PEK
PEN
PER
PNH
PUS
PVG
RGN
SGN
SIN
SYD
TPE (nonstop and with stop)
VNS (seasonal, no nonstop)
VTE
XMN
ZRH

Current international TG routes not from BKK
HKG-HKT
HKG-ICN
HKG-TPE
ICN-TPE
KHI-MCT
MNL-KIX
NRT-HKT

Discontinued international TG routes
BKK-GMP (SEL before ICN was opened)
BKK-JFK
BKK-JNB
GMP-LAX
HDY-SIN
KIX-LAX
NRT-LAX
NRT-SEA-DFW
NRT-TPE
TPE-SEA
SYD-AKL

Current domestic TG destinations from BKK
CEI
CNX
HDY
HKT
KBV
KKC
PHS
UBP
URT
USM
UTH

Current domestic TG routes not from BKK
CNX-HGN
CNX-HKT (O.W.)

Discontinued domestic TG routes
DMK-CEI
DMK-CNX
DMK-HDY
DMK-HKT
DMK-KKC
DMK-PHS
DMK-UBP
DMK-URT
DMK-UTH