Espeon is outclassed by nearly every offensive Psychic Pokemon out there because they're either stronger or faster than it and/or boast better offensive move pools. Examples include Lati@s, Alakazam, Mega Medicham, (Mega) Gardevoir and Speed Deoxys:
Speed Deoxys:
-Psycho Boost
-Ice Beam
-Superpower
-Knock Off/Stealth Rock
Nature: Hasty/Naive
EVs: 20 Atk/252 SAtk/236 Spe
Item: Life Orb
Alakazam:
-Psychic/Psyshock
-Shadow Ball
-Focus Blast
-Hidden Power (Ice)/Dazzling Gleam/Thunder Wave
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Focus Sash
Ability: Magic Guard
or
-Psychic/Psyshock
-Shadow Ball/Hidden Power (Fire)
-Focus Blast
-Taunt
Nature: Modest
EVs: 4 HP/252 SAtk/252 Spe
Item: Alakazite
Ability: Magic Guard
Latios:
-Draco Meteor
-Psyshock
-Earthquake/Thunderbolt/Hidden Power (Fighting)
-Defog/Recover/Roost
Nature: Hasty/Timid
EVs: 4 Atk/252 SAtk/252 Spe
Item: Life Orb
Latias:
-Draco Meteor
-Psyshock/Thunderbolt
-Defog
-Healing Wish
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb
Medicham:
-High Jump Kick
-Zen Headbutt
-Ice Punch/Fire Punch
-Fake Out/Substitute
Nature: Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Medichamite
Ability: Pure Power
Gardevoir:
-Psyshock
-Hyper Voice
-Focus Blast
-Shadow Ball/Taunt/Will-o-Wisp
Nature: Timid
EVs: 24 Def/232 SAtk/252 Spe
Item: Gardevoirite
Ability: Trace
or
-Calm Mind
-Psyshock
-Hyper Voice
-Shadow Ball/Taunt
Nature: Timid
EVs: 24 Def/232 SAtk/252 Spe
Item: Gardevoirite
Ability: Trace
or
-Psyshock
-Moonblast
-Focus Blast
-Trick/Healing Wish
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Scarf
Ability: Trace
If you want to keep Espeon, Dual Screening is the best it can do:
-Reflect
-Light Screen
-Baton Pass
-Psychic/Psyshock/Yawn
Nature: Timid
EVs: 252 HP/4 Def/252 Spe
Item: Light Clay
Ability: Magic Bounce
Mega Lucario is banned to Ubers if this is a Showdown! team. In Wi-Fi, Mega Lucario is okay, though it needs Aura Sphere for specially-based sets:
-Nasty Plot
-Aura Sphere
-Flash Cannon
-Dark Pulse/Shadow Ball/Vacuum Wave/Hidden Power (Ice)
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Lucarionite
Ability: Steadfast/Inner Focus
or
-Close Combat
-Iron Tail
-Bullet Punch
-Stone Edge/Swords Dance/Ice Punch
Nature: Jolly
EVs: 252 Atk/4 SDef/252 Spe
Item: Lucarionite
or
-Swords Dance
-Close Combat
-Extreme Speed
-Iron Tail/Earthquake/Ice Punch
Nature: Adamant/Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb/Lucarionite
Eelektross isn't that good, tbh. It has a wide move pool, sure, but its Speed is bad and its defenses are okay at best. Better Electric Pokemon to use are Wash Rotom, Zapdos, Thundurus or even Mega Manectric:
Wash Rotom:
-Volt Switch
-Hydro Pump
-Will-o-Wisp
-Pain Split/Rest
Nature: Bold
EVs: 248 HP/216 Def/44 Spe
Item: Leftovers/Chesto Berry
or
-Volt Switch
-Hydro Pump
-Hidden Power (Ice)/Thunderbolt
-Trick
Nature: Modest/Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Choice Scarf
Zapdos:
-Thunderbolt
-Defog
-Roost
-Heat Wave/Toxic/U-turn
Nature: Bold
EVs: 248 HP/168 Def/68 SAtk/20 Spe
Item: Leftovers
Thundurus:
-Thunderbolt
-Hidden Power (Ice)
-Focus Blast/Taunt
-Thunder Wave
Nature: Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Leftovers/Life Orb
Ability: Prankster
or
-Nasty Plot
-Thunderbolt
-Hidden Power (Ice/Flying)
-Focus Blast/Psychic/Thunder Wave/Substitute
Nature: Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Life Orb/Leftovers
Ability: Prankster
or
-Thunderbolt
-Knock Off
-Superpower
-Hidden Power (Ice)/Fly
Nature: Naive/Jolly
EVs: 76 Atk/180 SAtk/252 Spe or 252 Atk/4 Def/252 Spe
Item: Life Orb/Power Herb
Ability: Defiant
Physical Greninja is bad because its physical moves lack power compared to its Special ones. Ice Beam does a better job at covering Grass Pokemon than Bounce, as it doesn't need a charge-up turn. Regular Spikes are more useful than Toxic Spikes, IMO, since this team is relatively offensive:
-Hydro Pump
-Ice Beam
-Extrasensory
-Dark Pulse/Hidden Power (Grass/Fire)/Grass Knot/Spikes
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Focus Sash
Ability: Protean
Even though Sableye is defensively weak, it needs investment in its defenses so that it can at least have an easier time taking hits while it uses its status moves:
-Taunt
-Will-o-Wisp
-Recover
-Knock Off/Foul Play
Nature: Impish/Bold
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Prankster
Offensive EVs are pointless on Ditto, since when Imposter activates, it will already take on the opponent's EVs. The preferred nature for Ditto is Relaxed with 248 HP/252 Def/8 SDef so that in the event when 2 Ditto face each other, the slower one will come out on top in a Struggle war.