Ooh, I love the Gen 5 Pokemon.
Here are the types you don't have, and my personal suggestions. The best choices, in my opinion, are bolded.
Normal
Victini Victory's suggestions:
Cinccino. Great design, and with Skill Link, a great addition with only one weakness.
Grass
Victini Victory's suggestions:
Simisage. You should have gotten one earlier.
Whimsicott/Lilligant depending on your version. Both are excellent.
Amoonguss. All around great Pokemon, used one in White 2. Covers two types you don't have.
Ferrothorn. Another great Pokemon I used in White 2. Covers two types you don't have.
Ice
Victini Victory's suggestions:
None. But if you really want one, Beartic exists.
Poison
Victini Victory's suggestions:
Scolipede. This is an amazing early bug type. Covers two types you don't have.
Amoonguss. Same reasons as stated above.
Psychic
Victini Victory's suggestions:
Musharna. Available early, and you can get a hidden ability one.
Gothitelle.
Reuniclus. I used one in White 2 and it was excellent.
Bug
Victini Victory's suggestions:
Scolipede. Same reasons as above.
Crustle.
Escavalier. Great Pokemon for ingame, but requires trade to evolve.
Accelgor. Fast and strong.
Durant. Covers two types you don't have.
Rock
Victini Victory's suggestions:
Gigalith. Requires trade to evolve.
Crustle.
Ghost
Victini Victory's suggestions:
Cofagrigus
Jellicent. A GREAT wall, used it in White 2, but you already have a water type.
Chandelure. Fantastic Pokemon, but you already have a fire type.
Golurk. Ghost type with a cool factor. However, you already have a ground type.
Steel
Victini Victory's suggestions:
Excadrill. One of the best. However you already have a ground type.
Escavalier. Stated above.
Ferrothorn. Stated above.
Bisharp. However, you already have a Dark type.
Durant. Stated above.
