Landing craft
The enormous building program quickly gathered momentum. Such a high priority was assigned to the construction of LSTs that the previously laid keel of an aircraft carrier was hastily removed to make room for several LSTs to be built in her place. The keel of the first LST was laid down on 10 June 1942 at Newport News, Va., and the first standardized LSTs were floated out of their building dock in October. Twenty-three were in commission by the end of 1942. Lightly armored, they could steam cross the ocean with a full load on their own power, carrying infantry, tanks and supplies directly onto the beaches. Together with 2,000 other landing craft, the LSTs gave the troops a protected, quick way to make combat landings, beginning in summer 1943.

Other: 

Landing Craft Navigation (LCN): Nine-ton Landing Craft Navigation (LCN) were used by British "Combined Operations Assault Pilotage Parties" (Royal Marine and Special Boat Service crew) for surveying landing sites.

Landing Craft Control (LCC): The Landing Craft Control (LCC) were 56-foot (17 m) U.S. Navy vessels, carrying only the crew (Scouts and Raiders) and newly developed radar. Their main job was to find and follow the safe routes in to the beach, which were lanes that had been cleared of obstacles and mines. There were eight in the entire Normandy invasion (two per beach). After leading in the first wave, they were to head back out and bring in the second wave. After that, they were used as all-purpose command and control assets during the invasion.
Very small landing craft, or amphibians, were designed. The U.S.-designed Landing Vehicle Tracked, was an amphibious (and sometimes armored) personnel carrier. These were operated by Army personnel, not naval crews and had a capacity of about three tons. The British introduced their own amphibian, the Terrapin.

Landing Craft Utility (LCU): A Landing Craft Utility (LCU) was used to transport equipment and troops to the shore. It was capable of transporting tracked or wheeled vehicles and troops from amphibious assault ships to beachheads or piers.

The Landing Ship Dock (LSD) came as a result of a British requirement for a vessel that could carry large landing craft across the seas at speed. The first LSD came from a design by Sir Roland Baker and was an answer to the problem of launching small craft rapidly. The "Landing Ship Stern Chute", which was a converted train ferry, was an early attempt. Thirteen Landing Craft Mechanized (LCM) could be launched from these ships down the chute. The Landing Ship Gantry was a converted tanker with a crane to transfer its cargo of landing craft from deck to sea—15 LCMs in a little over half an hour.
The design was developed and built in the US for the USN and the Royal Navy. The LSD could carry 36 LCM at 16 knots. It had a large open compartment at the back. Opening a stern door and flooding special compartments opened this area to the sea so that LCI-sized vessels could enter or leave. It took one and a half hours for the dock to be flooded down and two and half to pump it out. When flooded they could also be used as docks for repairs to small craft.
Due to their small size, most amphibious ships were not given names and were just given serial numbers, e.g., LCT 304. The LSTs were an exception to this, since they were similar in size to a small cruiser. In addition, three British-built LSTs were named: HMS Boxer, HMS Bruiser and HMS Thruster; these were all larger than the U.S. design and had proper funnels.

Special craft: It was soon realized that battleships, cruisers and destroyers could not necessarily provide all the fire support (including suppressive fire) that an amphibious assault might need. Therefore, specialized vessels were developed that incorporated various direct and indirect fire weapons. These included guns and rockets which could be mounted on landing craft and landing ships. As part of the final barrage before an assault, the landing area would be plastered by these types.
Amphibious landing craft of WWII were generally fitted out with minimal weaponry. LCA crews were issued with .303 inch Lewis Guns, which were mounted in a light machine gun shelter on the forward-port side of the craft; these could be used both as anti-aircraft protection and against shore targets. Later models were fitted with two 2-inch mortars, and two Lewis or .303 Bren light machine guns. LCM 1 crews were issued with Lewis guns, and many LCM 3s had .50 in (12.7 mm) Browning machine guns mounted for anti-aircraft protection. Opportunities for troops on board to use their own weapons presented themselves.
LCIs and LCTs carried heavier weapons, such as the Oerlikon 20 mm cannon, on each side of the bridge structure. LSTs had a somewhat heavier armament.
Some landing craft were converted for special purposes either to provide defence for the other landing craft in the attack or as support weapons during the landing.

Landing Craft Assault (Hedgerow): The LCA(HR) was a converted British LCA. It carried a battery of 24 spigot mortars, the Royal Navy's Hedgehog anti-submarine weapon, instead of personnel. The mortars were fired as a barrage onto the beach to clear mines and other obstructions. Having discharged its mortars and its duty, the LCA(HR) would leave the beach area. They were towed to the beach by larger craft, such as the LCTs that carried the Royal Engineer assault teams with their specialist vehicles and equipment, who would complete the beach clearance.
Three flotillas (of 18, 18 and 9 craft) were used at Juno, Gold and Sword beaches.

Landing Craft Flak: The Landing Craft Flak (LCF) was a conversion of the LCT that was intended to give anti-aircraft support to the landing. They were first used in the Dieppe Raid early in 1942. The ramp was welded shut, and a deck built on top of the Tank deck. They were equipped with several light anti-aircraft guns—a typical fitting was eight 20 mm Oerlikons and four QF 2 pdr "pom-poms" and had a crew of 60. On British examples, the operation of the craft was the responsibility of RN crew and the guns were manned by Royal Marines. They carried two naval officers and two marine officers.

Landing Craft Gun: The Landing Craft Gun (LCG) was another LCT conversion intended to give supporting fire to the landing. Apart from the Oerlikon armament of a normal LCT, each LCG(Medium) had two British Army 25 pounder gun-howitzers in armoured mountings, while LCG(L)3 and LCG(L)4 both had two 4.7-inch naval guns (12 cm). Crewing was similar to the LCF. LCGs played a very important part in the Walcheren operations in October 1944.

Landing Craft Rocket: The Landing Craft Tank (Rocket), LCT(R), was an LCT modified to carry a large set of launchers for the British RP-3 "60 lb" rockets mounted on the covered-over tank deck. The full set of launchers was "in excess of" 1,000 and 5,000 reloads were kept below. The firepower was claimed to be equivalent to 80 light cruisers or 200 destroyers.
The method of operation was to anchor off the target beach, pointing towards the shore. The distance to the shore was then measured by radar and the elevation of the launchers set accordingly. The crew then vanished below (apart from the commanding officer who retreated to a special cubby hole to control things) and the launch was then set off electrically. The launch could comprise the entire set or individual ranks of rockets.
A full reload was a very labor-intensive operation and at least one LCT(R) went alongside a cruiser and got a working party from the larger ship to assist in the process.

Landing Craft Support: The Landing Craft Support was used to give some firepower close in.
The Landing Craft Support (Medium) (LCS(M)), Mark 2 and Mark 3 were used by the British forces at Normandy. The crew was Royal Navy, with Royal Marines to operate the weapons: two 0.5 inch Vickers machine guns and a 4-inch mortar to fire smoke shells.
The Fairmile H Landing Craft Support (Large) had armour added to its wooden hull and a turret with an anti-tank gun fitted. The LCS(L) Mark 1 had a Daimler armoured car turret with its QF 2–pdr (40 mm) gun. The Mark 2 had a QF 6–pdr (57 mm) anti–tank gun.
The American Landing Craft Support was larger, each was armed with a 3-inch gun (7.6 cm), various smaller guns, and ten MK7 rocket launchers.

Inflatable landing craft: Inflatable boats were often used to transport amphibious troops from high speed transports and submarines. The United States used a 7-man Landing Craft, Rubber (Small) (LCR-S) and a 10-man Landing Craft, Rubber (Large) (LCR-L).