Dragonite (From LeafGreen, now in Platinum, arrived at level 65.)
Togekiss (From LeafGreen, now Platinum, arrived at level 5.)
Vaporeon (From LeafGreen, now in Platinum, arrived level 69.) (Has Pokerus.)
Gengar (From Diamond, now in Platinum. Met at level 12 @ Old Chateau.)
Infernape (Platinum only. Starter.)
All are legit and I refuse to give them away.
I also have a Japanese Glaceon that's at level 100 but I never use it.
Pokemon close to level 100 are Floatzel 97, PorygonZ 92, Mr. Mime (aka Mimien from LG) 94. I also have level 80 Charizard, level 59 Garchomp, level 69 Luxray, Azumarill level 82, Leafeon 78, Gyarados level 82, Mewtwo level 71, Lopunny level 70, Blaziken level 78, Manectric 77. All are legit. I've used them in previous games (Emerald and LeafGreen) and migrated them into either Diamond or Platinum.
(I once had a level 100 Feraligatr in Silver, but my brother did a new game. :()