This is the team I used for Pokemon Black 2. I fell like this is the best team for anyone.
Availability: Early Game, Virbank Complex, 25% (Inside)
Stats: Has a great Special Attack stat, with decent overall bulk to back it up.
Typing: Steel/Electric is arguably the holy grail of defensive typings, with resistances to everything bar four types. Ground and Fighting types are rather common though. Offensively, this typing is mediocre, but is saved by its stats and movepool.
Movepool: Magnemite comes with Sonic Boom, a godsend early game that can 2HKO everything. Aside from that, it has Thundershock, and later Mirror Shot. Magnemite doesn't get any good STAB moves until Flash Cannon, but it can hold on with STAB Volt Switch, Thunder, and a tutored Signal Beam.
Major Battles: Magnemite steamrolls over Roxie, Burgh, Skyla, and Marlon by virtue of typing alone. It helps a lot against Drayden, but needs to watch out for coverage moves such as Earth Power.
Stats: Balanced stats across the board, with some emphasis in Attack and Special Attack.
Typing: Water gives it a nice variety of options, but it doesn't give Oshawott a lot of strong matchups throughout the game.
Movepool: Oshawott gets interesting movepool options, most notable being Megahorn from the move relearner (or X-Scissor from TM), Superpower from move tutor, and Ice Beam and Blizzard from TM. It also gets Swords Dance, allowing it to pull off sweeps on some foes.
Major Battles: Oshawott is one of the best options against Clay, an otherwise difficult battle. Its coverage options make it a legitimate pick for Drayden as well. In the E4, Samurott shines as a backup to almost everything, with a strong varied movepool to pick off weakened teams.
Availability: Early-Mid Game, Route 4, 5%
Stats: Scraggy has solid Attack and defenses. Upon evolving, its defenses overtake its Attack, meaning it remains bulky before and after evolution. It’s fairly slow though.
Typing: Dark + Fighting make a great combo, only Heracross and Toxicroak resist them, both of which are rarely seen.
Movepool: Scraggy starts off with Faint Attack and Headbutt, then gets Brick Break at level 20. It gets Payback, Hi Jump Kick, and finally Crunch right before evolving. It gets Rock Tomb by TM, and Ice Punch through tutoring.
Major Battles: With access to Dig and Rock Tomb, Scraggy can take on Elesa easily. Its Fighting attacks do well against Clay's Krokorok and Excadrill. Crunch can take out Skyla's Swoobat. With its bulk and strong attacks, Scraggy can go head-to-head to Drayden, watch out for Druddigon's Revenge. Scraggy manhandles Marlon's Jellicent and stomps both Zinzolin and Colress, while taking on any of Ghetsis's team bar Toxicroak. Scraggy has positive matchups against 75% of the Elite Four and takes on most of Iris's team.
Availability: Early-Mid Game, Desert Resort, 10% (Desert)
Stats: Its stats are well distributed for in-game runs. High Special Attack and Speed and its defenses are more than enough to take hits repeatedly when required.
Typing: Psychic/Flying STAB provide plenty of neutral and super effective coverage, but they are stopped by Steel-types. 4x Fighting resistance and Ground immunity are helpful. It has 5 weaknesses but some of those are rare.
Movepool: Air Cutter and Psybeam provide early power, and Air Slash and Psychic replace these to keep it going late-game. Shadow Ball from TM is useful for coverage on Psychic-types, and Signal Beam is a more expensive alternative for both Psychic- and Dark-types. It gets walled by Steel-types for most of the game, so Heat Wave is an option late-game if you have the shards.
Major Battles: It can use its STABs to beat most Team Plasma grunts. Its typing is only advantageous against Marshall (watch out for Rock attacks), but it has enough power and Speed to at least contribute against pretty much any gym.
Availability: Early Game, Virbank Complex, 20% (Inside)
Stats: They’re very balanced. Its Attack and Special Attack are equally usable, and it's fairly fast too. It's also quite bulky, with good HP and average defenses.
Typing: Fire is a decent type in this game. It hits a good amount of Pokemon for super effective damage, but it's weak to Water, Ground, and Rock, all of which are very easy to take advantage of.
Movepool: Shallow. It learns nothing useful by level-up, except for STAB moves, Outrage and Crunch; Extremespeed is decent, but isn't very useful. To get its best physical STAB, Flare Blitz, you have to keep it as a Growlithe until level 45, which sucks. It can't learn Wild Charge, its best supplemental coverage, until Victory Road, at which it's pointless. Thunder Fang is available, but is a rather poor move in general.
Major Battles: It can be a good asset against Roxie, and it destroys Burgh and Colress. Other than those two, it doesn't do particularly well against any other important trainers, but it's only really useless versus Drayden and Marlon.
Availability: Early-Mid Game, Desert Resort, 5% (Desert)
Stats: It’s very strong, but frail and slow at the same time. But, once it gets to Flygon, all of its stats are respectable, especially with high Speed and Attack.
Typing: Ground is a solid typing, but having some common weaknesses makes it have a hard time. As Vibrava and Flygon, its secondary Dragon-type removes some of them, while it provides a great secondary STAB.
Movepool: Sadly, it can't get Earthquake during the main story unless you keep it as a Trapinch until level 55. Dig or Earth Power serve as substitutes, though, and it learns Dragon Claw by level-up. It gets nice coverage moves like Fire Blast and Rock Slide. You can also use it for Fly.
Major Battles: It does really well against Elesa. It can also do work against Skyla with Rock Slide, while Dragon Claw helps against Drayden. Its Ground-type moves will be helpful against most of Team Plasma.