* Grass/Dragon: Serperior, Sawsbuck, Virizion
* Dark/Ghost: Chandelure, Jellicent
* Dark/Dragon: Hydreigon
* Dark/Fighting: Scrafty
* Ice/Dragon: Dragalge
* Electric/Dragon: Zekrom
* Fire/Dragon: Reshiram
* Steel/Dragon: Axew, Fraxure, Haxorus
* Rock/Electric: Jolteon
* Steel/Psychic: Metagross
These are just some of the new types introduced in Black and White. There are many more new Pokemon with unique type combinations!
It's important to note that some of the above types existed before Black and White, but were not widely available until then. For example, Jolteon is an Electric/Rock type, but it's not commonly known for that type combination.
Do you want to learn more about specific new Pokemon or their types?