Short List

NST - National Standard Thread. Same as GHT (Garden Hose Thread) or NH (National Hose)
GHT - garden hose, used also in fire hose [1]. Same threads per inch as NPT, but not tapered.
NPSH - same as NPS [2]. Compatible with NPT [3]
NPS - National Pipe Straight, same as NPT, but straight. [4]. 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 - [5]. Only NPT with chamfer will seal properly with NPSM - other NPT threads may not seal.
NPT - National Pipe - tapered
R, G - [6]
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 - [7]
SAE - with o-rings

Long List

Probably hundreds exist all together.