im on the fence about capturing tynamo to get elektross but not sure if its worth it? it has no weakness though keep that in mind (if it is whats a good moveset for it thnx)
Eelektross is a gimmick, it has no weaknesses but below average defenses, not that hard to take down, and any Pokemon with Mold-breaker is able to use ground type moves on it. He can be good when used properly, for example: a coil set can make him Physically bulky, and he can be destructive with Trick-room support. He is a decent Pokemon but do not use him because having no weaknesses makes him invincible because it doesn't.
As for the moveset: http://pokemondb.net/pokebase/13517/what-is-a-good-moveset-for-eelektross