There are too many legendaries these days and most of them are shit.

Kanto
Mascots - N/A
Trio - Articuno, Zapdos, Moltres
Kingpin - Mewtwo
Hidden - Mew

Johto
Mascots - Ho-Oh, Lugia(Changed to Flying/Water)
Trio - Raikou, Entei, Suicune
Kingpin - N/A
Hidden - Celebi

Hoenn
Mascots - Latias, Latios
Trio - Regirock, Regice, Registeel
Kingpin - Deoxys(Changed typing etc to be less of a Mewtwo rehash)
Hidden - Jirachi

Sinnoh
Mascots - Cresselia, Darkrai
Trio - Uxie, Mesprit, Azelf(Changed typings etc to be not so fucking boring)
Kingpin - Heatran (Buffed appropriately for the role)
Hidden - Manaphy

Unova
Mascots - Reshiram, Zekrom
Trio - Cobalion, Terrakion, Virizion
Kingpin - Kyurem
Hidden - Meloetta
Bonus - Genesect

Kalos
Mascots - Xerneas, Yveltal
Trio - N/A
Kingpin - Zygarde
Hidden - Diancie

There, I fixed legendaries as best I could. You can thank me later.