Eelektross is #604 in the national pokedex, and it is an Electric type Pokemon.
Eelektross has no type weaknesses. Though Electric, it is immune to Ground-type attacks because of its ability Levitate. However, if Eelektross' ability is negated or changed, then Ground-type attacks will do twice as much damage.
Eelektrik - Eelektross
The only new one to use thunder stone is Eelektrik to Eelektross. Then you have your Pikachu/Raichu and Eevee/Jolteon.
There's blitzle and zebstrika, tynamo, eelekrik and eelektross, joltik and galvantula, emolga, and finally, stunfisk.
I would prefer Eelektrik and Eelektross Because they have an immunity to ground (Please correct if I'm wrong, it may be another pokemon, or this is unobtainable in White).
If you can't find it, involve electrik into elektross.
The new Electric Pokemon introduced in Black and White are: Blitzle & Zebstrika Emolga Joltik & Galvantula Tynamo, Eelektrik, & Eelektross Stunfisk Thundurus Zekrom
she has a lvl 75 spiritomb, milotic, eelektross, braviary and lucario and a lvl 77 garchomp
first you need a strong party. i think it will be: jellicent,haxorus,zekrom or reshiram,emboar,bisharp and eelektross. and she use:spiritomb,garchomp,braviary,eelektross,milotic and lucario. !
It evolves: Eelektric into an Eelektross Pikachu into Raichu Eevee into Jolteon
Tynamo evolves into Eelektrik at lv. 39, give it a thunderstone and it evolves into Eelektross.