The M4 Sherman was the most famous tank of WW2, with a 75mm rifled gun, with 3 inches to .5 inches of armor thickness. These have appeared in the movie "Fury", not the one that the main characters are in, but the other Shermans.
The M4 Composite was the Sherman but with a cast front and a welded back. You can tell the difference by if the front hull is rounded or not.
The M4(105) was the M4 Sherman with a 105mm mortar instead of the 75mm. These were designed for infantry support and assault, but it got rid of their anti-armor capabilities.
The M4(105) HVSS was the M4(105) but with a different suspension system.
This Sherman had a cast hull and a different engine, as well as later on a larger driver's hatch. Still with the 75mm gun.
The M4A1(76)W had a 76mm gun to counter German armor, and the larger drivers hatch.
The M4A1(76)W HVSS is the M4A1(76)W but with a widetrack HVSS and the 76.
The M4A1E9 was a late-war remanufacturing with the VVSS suspension, and was used by many countries after the war. These appeared before the victory day.
The M4A2 was the M4A1 but with slightly less gun depression but better armor. This armor helped against German 88mm guns and the Panzerfaust.
The M4A2(76)W was the M4A2 but with the 76mm gun, and large driver hatches. This was used only by the USSR.
The M4A2(76)W HVSS was the M4A2(76)W but with a wider track and better suspension.
The M4A2E4 used the torsion bar suspension, had better tracks, and it was too complicated so the discontinued their production. Only 2 were built, both prototypes.
The M4A3 had either the 75 or 76mm gun on it, and this was the standard US army vehicle. With it having a welded hull, it had the sharper angles on its front.
The M4A3(75)D was the 75mm M4A3 with dry ammunition storage. These were mostly training units.
The M4A3(75)W was the same as above but with wet ammunition storage. This decreased risk of fire and had them on the hull floor for safety.
The M4A3(75)W HVSS was the same as above but with a HVSS suspension system.
The M4A3(76) was the M4A3 with the 76mm gun.
The M4A3(76) HVSS was the same as above - but with a HVSS suspension system.
The M4A3(105) was the M4A3 designed for infantry support with a 105mm mortar.
The M4A3(105) HVSS was the same as above but with HVSS.
The M4A3E2 Assault Tank had thicker armor, with enough to withstand the German 88s, most with 75mm guns, but some with 76mm guns from other damaged tanks. This tank is referred to as the "Jumbo"
The M4A3E4 was an idea to make the 76mm gun standard on the Jumbo, while thought of by the US, the US didn't go through with it, but other countries did.
The M4A3(76)W HVSS (M4A4E8) is by far one of the largest names, sometimes called the Easy 8, it had the 76mm gun, wet ammunition storage, and the HVSS suspension.
The M4A4 had a lengthened hull, made of cast iron. It only had the 75mm gun. The US didn't use it, but it was known as the Sherman Firefly. The M4A4E1 was just the M4A4 but with a 105mm mortar. They put it on a T70 mount, and made the M4E5 pilot vehicle.
This was just an unused name for the Canadian Ram tank.
The M4A6 used the M4A4's hull, with a 75mm gun, a Caterpillar D200A turbocharged air-cooled engine, and a welded/composite hull. 75 were made because the engine supply was low. These did not see combat.
The 105mm Howitzer Motor Carriage M7 was a self-propelled 105mm howitzer based on the M3, M4 and M4A3.
The 155mm Gun Motor Carriage M12 was a 155mm gun on a GMC.
The Cargo Carrier M30 was a M12, but a cargo carrier, with ammunition instead of a gun.
The 155mm Gun Motor Carriage M40 was the same as the M12 but only on the M4A3 HVSS chassis.
The 8in Howitzer Motor Carriage M10 was a tank destroyer that was based on the M4A2 Sherman chassis.
The 3in Gun Motor Carriage M10 was a tank destroyer based off of the M4A2 Sherman chassis.
The 3in Gun Motor Carriage M10A1 was the same as above but based off of the M4A3 Sherman chassis.
The 90mm Gun Motor Carriage M36 was a tank destroyer based off of the M10A1 hull.
The 90mm Gun Motor Carriage M36B1 was the same as above but with both the M4A3 hull and chassis.
The 90mm Gun Motor Carriage M36B2 was a tank destroyer based on the M10 hull, but with the M4A2 chassis. It also used diesel.
The Tank Recovery Vehicle M32 was based on the M4 with a fixed turret instead of the normal turret and gun. It had a winch and 18-foot pivoting A-frame jib installed. Some had an 81mm mortar on them.
The M74 Tank Recovery Vehicle was an upgrade of the M32 with a frontal spade and built to be used postwar.
The M34 Prime Mover was the M32B1 TRV changed to an artillery tractor for big guns.
The M35 Prime Mover was the M10A1 changed to house 240mm guns.
The Demolition Tank T31 had a 105mm howitzer as its main gun and 2 7.2 inch rocket tubes mounted on each side with a M4A3 HVSS chassis.
The Multiple Gun Motor Carriage was a 40mm autocannon with 2 .5 inch machine guns put in a ball turret on a M4 chassis. It was discontinued after trials in 1944.
The 90mm Gun Motor Carriage T53/T53E1 was a 90mm gun mounted on a M4A4 chassis. It was supposed to be used as both an anti-tank and anti-aircraft but the tank destroyer and AA corps in the U.S. Army rejected it, so they scrapped the idea.