CL - compassionate leave
LA - annual leave with wraparound days after x4
LB - annual leave with wraparound days before x3
WR - wrap around days off (workable)
BW - bank withdrawal
SW - not sure off the top of my head
S2, S3, S4, S5 - simulator. The number refers to the time slot. I2, I3, I4, I5 would refer to the instructor’s roster.
NA - non-assignable day associated with DD usually
DD - duty free week associated with NA day at the beginning. Can be worked in if desired.
ZZ - break, usually to denote days off after a trip on reserve
RP - reserve period
PR - protected day off, for a variety of reasons
PL - not sure EDIT: paternity leave
PD - part-time days off
GT - ground training e.g. SEP
GD - ground duty
LFS - Leading Flight Safety course
FDO - fixed days off associated with a reserve period
HSB - HSB associated with a reserve period
Depending on the roster format you’re looking at but you can usually tell by the destinations.