Other ancient reptiles

Marine Reptiles:

Ichthyosaurus: Dolphin-like body shape, large eyes, powerful tail flukes.

Plesiosaurus: Long neck, small head, four paddle-like flippers.

Liopleurodon: Massive size, large, broad skull, powerful jaws.

Mosasaurus: Large, lizard-like body, powerful jaws, strong tail fin.

Nothosaurus: Long neck, flattened skull, webbed feet (transitional form).

Tanystropheus: Extremely long neck (several times the length of its torso).

Placodus: Blunt teeth for crushing shellfish, bony armor on its back.

Elasmosaurus: Exceptionally long neck.

Pliosaurus: Short, powerful neck, massive head with conical teeth

Atopodentatus: Marine reptile with a "zipper-like" toothed upper jaw split down the middle.

Dinocephalosaurus: Aquatic protorosaur with an extremely long neck, making up more than half its body length.

Hypuronector: Elongated body and large eyes. Large, paddle-shaped hands and feet. 

Pterosaurs:

Pterodactylus: Relatively small, long beak, no bony crest.

Pteranodon: Large pterosaur, prominent backward-pointing crest.

Nyctosaurus: Distinctive, long, antler-like crest on its head.

Rhamphorhynchus: Long tail with a diamond-shaped vane, forward-pointing teeth.

Tapejara: Prominent, often elaborate crest on its snout and head.

Quetzalcoatlus: Enormous wingspan.

Dimorphodon: Large, robust head, relatively short wings.

Dsungaripterus weii: Upward-curving lower jaw and a prominent head crest starting midway along its snout.

Pterodaustro: Long, upward-curved lower jaw filled with hundreds of bristle-like teeth for filter-feeding.

Crocs:

Sarcosuchus: Enormous size, bulbous growth at the tip of its snout (bulla).

Stomatosuchus: Long-snouted crocodylian, needle-like teeth.

Kaprosuchus: Heavily armored snout, large, forward-projecting canine-like teeth ("Boar Crocodile").

Simosuchus: Short, blunt snout, leaf-shaped teeth ("Pug-nosed Crocodile").

Anatosuchus: Flattened, duck-like snout.

Champsosaurus: Resembled a gavial, extremely long, slender snout.

Dakosaurus: Short, broad snout, large, serrated teeth.

Suchomimus: Long, slender snout, sail on its back.

Thalattosuchus: Marine crocodylomorph with paddle-like limbs and a hypocercal tail fluke like an ichthyosaur.

Other Prehistoric Reptiles:

Dimetrodon: Large "sail" on its back (elongated neural spines).

Edaphosaurus: Similar to Dimetrodon but with crossbars on the spines of its sail. These two are technically closer to mammals than they are to reptiles, cladistically speaking.

Scutosaurus: Bony scutes covering its body.

Pareiasaurus: Bony knobs and ridges on its skull and body.

Captorhinus: Multiple rows of teeth in its jaws.

Proterosuchus: Long snout with a downturned tip (crocodile-like appearance).

Coelurosauravus: Archosauromorph with elongated ribs forming a gliding apparatus, similar to a flying squirrel.

Cotylorhynchus: Large synapsid with a disproportionately tiny head and a massive, barrel-shaped body

Drepanosaurus: Arboreal reptiles with chameleon-like eyes, bird-like heads, grasping hands and feet, a claw at the end of their prehensile tail, and a hump on their back.

Erythrosuchus: Large, predatory archosauriforms with disproportionately large, massive heads.

Estemmenosuchus: Large, herbivorous therapsid with multiple horn-like structures on its skull.

Hupehsuchus: Enigmatic marine reptile with a long, narrow, toothless snout, split dorsal plates, and extensive body armor.

Longisquama: Small reptile with extremely long, ribbon-like scales (or feathers) projecting from its back.

Odontochelys: Early turtle with a fully developed plastron, a partial carapace, and teeth.

Vancleavea: Medium-sized archosauriform characterized by its unique arrangement of osteoderms and elongated body.

Eunotosaurus: A parareptile with broad, flat ribs that were believed to be an early step towards the development of the turtle shell, although not directly related to turtles. 

Drepanosaurus: A reptile with a very short, triangular-shaped skull, a chameleon-like grasp, and an exceptionally long, curved claw at the end of its tail. 

Sharovipteryx: A bizarre gliding reptile with a membrane of skin between its legs, rather than its arms. It had long, slender legs and a tail, with its wings located between its hindlimbs and its tail. 

Cotylorhynchus: Pelycosaurs with extremely robust bodies, small heads, barrel-shaped rib cages, and powerful limbs with thick bones.

Sclerocephalus: A large, amphibian-like temnospondyl with a very broad, flat head, a short snout, and many teeth, including fang-like teeth on the roof of its mouth. 

Trilophosaurus: A reptile with a surprisingly short and blunt snout, often likened to a bird's beak, with powerful teeth adapted for crushing plant material.