2018 Eggstravaganza event took place between March 22nd and April 2nd, 2018.
During this event, there were only 2-km Eggs obtainable from PokéStops. From each 2-km Eggs there was a chance of hatching one of Pokémon that were normally hatching from 5-km and 10-km Eggs. Moreover, trainers received bonus Candy for each hatched Pokémon and double Stardust for various actions in the game. 
Following Pokémon hatched from 2-km Eggs during this event: