To sought this out, this is what types we have had for legendaries.
Fire - Moltres, Entei, Groudon, Heatran, Ho-Oh.
Water - Kyrogue, Suicune, Phione, Manaphy. Lugia.
Electric - Zapdos, Raikou.
Grass - Shaymin, Celebi.
Psychic - Mew, Mewtwo, Celebi, Jirachi, Azelf, Mesprit, Uxie, Jirachi, Deoxy...