Colored energy cards are sometimes used to aid the Pokemon. There are four basic types of cards. Basic Pokemon cards which depict creatures that fight for you against other people's Pokemon. Evolution cards depict Pokemon that are able to evolve into more powerful creatures. Energy cards are united with other cards to give the Pokemon more energy needed in carrying out the trainer's orders.
Trainer cards are cards used one time and then discarded.
Within each type are several different Pokemon each possessing various abilities. I've constructed a chart below of some of the categories of Pokemon. Psychic Abra, Kadabra, Alakazam, Drowsee, Hypno, Jynx, Mew, Mewtwo, Mr. Mime Reading minds, teleportation, inducing headaches, high intelligence, consumes people's dreams, hypnosis, confusion, evolves. Within the game evolution is taught repeatedly. Of course, after normal development in skill learning, various Pokemon often evolve on their own.