Short List

National Hose (NH). It is also called National Standard Thread (NST) or National Hose Thread (NHT). It is often referred to as “fire hose thread”. NH, NST and NHT are different abbreviations - [1]
NST - National Standard Thread. Same as GHT (Garden Hose Thread) or NH (National Hose)
GHT - garden hose, used also in fire hose [2]. Same threads per inch as NPT, but not tapered.
NPSH - national pipe straight hose - same as NPS [3]. Compatible with NPT [4]. NPSH has the same threads per inch as NPT, but without taper. [5]. Verified here [6].
NPS - National Pipe Straight, same as NPT, but straight. [7]. NPS is not used for high pressure, while NPT can be, such as hydraulics. Does this mean that NPS and GHT are the same?
NPSM - National Pipe - Straight Mechanical - closure attained by 30 degree compression fit with a swivel - [8]. Only NPT with chamfer will seal properly with NPSM - other NPT threads may not seal.
NPT - National Pipe - tapered
R, G - [9]
BSPP - British Pipe thread parallel
BSPT - British Pipe thread tapered
Bolt thread - fine and course
Metric bolt - fine and course
Metric pipe straight
Metric pipe parallel
UN - [10]
SAE - with o-rings

Long List

Probably hundreds exist all together.