The COMMON Mooneys you see are all M20s.
But lots of different models of M20s.
M20 - Original with wood wing and 150 HP Lycoming O-320
M20A - Wood wing, 180 HP Lycoming O-360
M20B - Metal wing 180 HP Lycoming
M20C - Metal and 180 HP Lycoming, also known as Mark 21 and Ranger
M20D - Fixed gear training, convertible to retract, most have been converted. Converted, they become the same as an M20C
M20E - 200 HP Lycoming IO-360, known as Super 21
M20F - 200 HP Lycoming, stretched 10 inches, Executive 21. First of the "mid body" models. The ones before became "short body" models
M20G - 180HP Lycoming, streched.
M20J - 200HP Lycoming IO-360, mid body, aerodynamic clean up, called the 201. Basically a faster M20F
M20K 231 - 210 HP turbo charged 6 cylinder Continental TSIO-360 (-GB or -LB) engine
M20K 252 - 210 HP turbo Continental TSIO_360-MB with intercooler and auto wasategate
M20K Encore - change from -MB to -SB engine, 220 HP, higher gross weight
M20L - aka PFM, Porsche 217 HP engine, stretched again to become the "long body" models, most converted to IO-550
M20M - aka TLS for Turbo Lycoming Sabre aka Bravo. Long body, Lycoming TIO-540, 270 HP
M20R - Ovation/Ovation 2, long body, IO-550 Continental, 280 HP. STC available to go to 310 HP
M20S - Eagle, IO-550 rated at 244 HP.
M20T -Predator, concept for military training with bubble canopy, sticks instead of yokes, Lycoming AEIO-540, only one built
M20TN - Acclaim, Turbo Normalized TSIO-550, 280 HP
M20U - Ovation Ultra, doors on right and left side. IO-550, 280 HP
M20V - Acclaim Ultra, doors on both sides. TISO-550, turbo normalized, 280 HP