If held by either parent of a Pichu when the Egg is produced, the Pichu that hatches will know the move Volt Tackle. From Generation VI onward, if a Pichu knows Volt Tackle this way (and was bred in Generation VI onward), it can be taught Volt Tackle again at the Move Reminder if it forgets the move.
In Pokémon: Magikarp Jump, Light Ball is a Friendship Item that is received as a reward after beating the Friend League. It summons Pikachu as a helper Pokémon.
Light Ball is introduced as a Pokémon Tool card in the Pokémon Trading Card Game during the English Mega Evolution Series (the Japanese MEGA Series). It was first released in the Japanese MEGA Dream ex subset before debuting in the English Ascended Heroes expansion, with artwork by Studio Bora Inc. Like its video game counterpart, the Light Ball card benefits the Pikachu ex it is attached to, making its attacks do 50 more damage to the opponent's Active Pokémon ex.
Trivia
Because Pikachu cannot be found in the wild in Unova, Thief and similar moves no longer permanently steal items held by Trainers' Pokémon from Generation V onward, and Poké Transfer does not transfer held items, the Light Ball cannot be obtained in Generation V outside of events. However, it is coded to be an item held by wild Pikachu, with a 1%*BW/5%B2W2 probability.