List of animals with jointed legs?

Answer 1

Jointed legs only appeared (as far as I know) twice in the animal kingdom:

• Tetrapods (ex. caecilians, snakes) - Literally "four feet" in Greek, this group includes amphibians, reptiles, birds, and mammals. Some lines, like the caecilians and the snakes, secondarily lost their limbs, but they are included as tetrapods due to evolutionary kinship and other shared characteristics, like having a neck. All descend from the 375-million-year-old "fishapod" Tiktaalik, which first bore limbs and a neck.
• Arthropods - This phylum of animals actually means "joint-legged", and includes the insects, arachnids, crustaceans, centipedes and millipedes, trilobites, horseshoe crabs and sea scorpions, and many others. This group is defined (as the name indicates) by its members having jointed legs and, to keep it separate from the tetrapods, a chitinous armour.

Answer 2

The only animal that has legs that aren't jointed is the penguin.