Use Earthquake over Shadow Ball, and switch him out if he comes up against Shedinja or another levitating Ghost-type.
You won't be able to use two pokemon with Leftovers since you can't repeat items in the Frontier.
Arcanine
Lonely/Mild nature
-Flamethrower
-Crunch (breed with Seviper)
-Extremespeed
-Hidden Power (Electric/Grass)/Iron Tail
More special oriented attacks along with Extremespeed.
Arcanine
Lonely/Brave nature
-Overheat
-Extremespeed
-Iron Tail
-Aerial Ace
More physically oriented, and Overheat can work well since it's the only special attack. Extremespeed can somewhat compensate for the speed drop of the nature, should you chose to go that route, but either way, Extremespeed should be on the set. Iron Tail is to hit Aerodactyl and other Rock-types, and Aerial Ace can help handle Double Teamers. They don't look like such great moves, but unfortunately it's the extent of Arcanine's physical attacks.
Slowbro
Modest/Quiet nature
-Surf
-Psychic
-Ice Beam
-Flamethrower/Substitute/Focus Punch
My favorite pokemon, and my water-type of choice in the Frontier. Surf is the primary move. Psychic is mostly used to handle opposing water-types, or anything it may be super effective against. Ice Beam is mostly for Dragon-types, but could be used against anything it would do more damage to than the other moves. Flamethrower is pretty situational, and it's only really to get more damage done to Steel-types. Substitute can be used to prevent status, particularly Toxic. I have Focus Punch on mine in case it becomes the last pokemon and it's up against a Blissey or something like that, but it's not the greatest move.
Exeggutor
Modest nature
-Sunny Day
-Solarbeam
-Psychic
-Hidden Power Fire
This could work well in 2vs2 along with Arcanine using Sunny Day, and then Exeggutor can immediately get started despite its slow speed due to its Chlorophyll ability. Some other options include Leech Seed, Sleep Powder, Stun Spore, Explosion, and breeding for Synthesis/Moonlight in place of Sunny Day or Hidden Power Fire if you don't want to use that. However, I recommend Hidden Power Fire in order to hit steel-types.
Weezing @ Choice Band
Adamant nature
-Sludge Bomb
-Shadow Ball
-Explosion
-Hidden Power (Ground/Fighting)/Flamethrower
Basic Choice Bander. The last move is to hit steel-types.
Weezing
Brave/Relaxed nature
-Sludge Bomb
-Shadow Ball/Explosion/Flamethrower/Thunderbolt/Pain Split/Will o wisp
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Use whatever moves will be most beneficial to your team.
Rhydon @ Choice Band
Adamant/Impish/Careful nature
Rock Head ability
-Earthquake
-Rock Slide
-Megahorn
-Double Edge
Choice Bander.
Rhydon
Adamant/Impish/Careful nature
-Earthquake
-Rock Slide
-Megahorn
-Swords Dance
This set can be a little riskier, but it allows you to switch moves, and use Swords Dance when you get a decent opportunity.
Aerodactyl @ Choice Band
Adamant nature
Rock Head ability
-Wing Attack
-Rock Slide
-Earthquake
-Double Edge
Kind of like the Rhydon, except a lot faster and with Wing Attack in place of Megahorn. You could teach it Aerial Ace over Wing Attack, but only if you can clone the TM first.
Heracross
Adamant nature
-Megahorn
-Brick Break
-Rock Slide
-Swords Dance
A lot of people like Reversal, but it's only useful when you're on low health, so it's rather risky.
Skarmory @ Choice Band
Adamant nature
-Drill Peck (Breed with Fearow/Doduo)
-Steel Wing
-Rock Slide
-Hidden Power Fighting/Ground
Meh, I don't use defensive sets, I'll leave that to someone else. If you want more offense, try this.
Kingdra
Mild nature
-Surf
-Ice Beam
-Dragon Breath (breed with Altaria)
-Return
Dragon Breath is nice to hit opposing water-types. Return is to hit Blissey and friends.
Aggron
Adamant nature
-Rock Slide
-Iron Tail
-Substitute
-Focus Punch
Sub-puncher. Other offensive options include Double Edge with the Rock Head ability and Earthquake, if you don't like Iron Tail's accuracy, but it is his strongest non-Focus Punch move. If you're not using Double Edge, I would suggest the Sturdy ability since there are people in the Frontier who use One-Hit-KO moves.
Medicham
Lonely/Naughty nature
-Brick Break
-Shadow Ball
-Thunder Punch
-Ice Punch
The first two moves are his only decent physical attacks. The elemental punches are special, and should only be used in a situation where they're really needed, such as against Skarmory.
Metagross @ Choice Band
Adamant nature
-Meteor Mash
-Earthquake
-Explosion
-Sludge Bomb/Rock Slide/Aerial Ace
Sludge Bomb can handle Ludicolo and Zapdos, Rock Slide can handle Zapdos and Gyarados, and Aerial Ace is useful in the Frontier to handle Double Teamers and Ludicolo.
