Josh, I added a few more, and removed some that were duplicated in your list. I also added some
SI - Self injury or self injuring
DSH - Deliberate self harm or deliberate self harming
SH - Self harm or self harming
ED - Eating disorder
PTSD - Post traumatic stress disorder
BP - Bi-Polar
BPD - Borderline Personality Disorder, also Bi-Polar disorder
OD - Overdose
Trig - Triggering
SU/SUI - Suicide, although tags shouldn't actually say SU/SUI
Adult- Mature/sexual content
b/p - binge/purge
Ana - Anorexia
Mia - Bulimia
COE - Compulsive Over Eating
COED - Compulsive Over Eating Disorder
CPTSD - Complex PTSD (Similar to PTSD)
OH - Occupational Health Or Other Half [partner]
OCD - Obsessive Compulsive Disorder
PR - Post Report
OP - Original Poster
E&MU - Events and Meet Ups board
Intros - Introductions board
GC - General Chat (forum name)
F&CQ - Forum & Community Questions
FA - First Aid (forum name)
FAA - First Aid Advisor
SD - Serious Discussion (forum name)
SID - Self Injury Discussion (forum name)
Vets - Veterans forum, also the who posts there regularly
R&R - Reviews and Recommendations board, generally
tbh - to be honest
FTW - For the win
QFT - Quoted for truth