Individual team members:
Dragon Dance Tyranitar is best off with the Tyranitarite and a Jolly nature to fully take advantage of the Speed boost Dragon Dance provides. Without either of those things, Greninja still outspeeds it even at +1 Speed.
Ampharos is only good in its Mega form; it has better coverage options than Signal Beam and Power Gem. Also, its current EV spread is inefficient; those last EVs should've been spent on HP, helping out its overall bulk:
-Volt Switch
-Dragon Pulse
-Focus Blast
-Thunderbolt/Discharge/Heal Bell
Nature: Modest
EVs: 236 HP/252 SAtk/20 Spe
Item: Ampharosite
Ability: Static
Gardevoir is only good either in its Mega form or as a Choice Scarf revenge killer. Timid is the superior nature for it, as a +Speed nature and Choice Scarf together means that Gardevoir actually has useful Speed to revenge kill stuff. Mega Gardevoir's Speed is also at an acceptable base 100, so taking advantage of that is best:
-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: 252 SAtk/4 SDef/252 Spe
Item: Choice Scarf
Ability: Trace
Why Fire Blast on a Jolly Dragonite? Extreme Speed is also a necessary move on it to let it get the jump on Talonflame and Choice Scarf users:
-Dragon Dance
-Outrage/Dragon Claw
-Earthquake
-Extreme Speed
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Lum Berry/Weakness Policy
Ability: Multiscale
or
-Outrage
-Earthquake
-Extreme Speed
-Dragon Claw/Fire Punch
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Choice Band
Ability: Multiscale
or
-Dragon Claw
-Earthquake
-Extreme Speed
-Roost
Nature: Adamant
EVs: 216 HP/64 Atk/228 SDef
Item: Leftovers
Ability: Multiscale
Metagross isn't good now because of its new weaknesses to Ghost and Dark. Knock Off is also everywhere. But if you insist on using it:
-Meteor Mash
-Zen Headbutt
-Earthquake
-Hammer Arm/Pursuit
Nature: Adamant
EVs: 252 HP/252 Atk/4 SDef
Item: Assault Vest
Ability: Clear Body
Okay, let's clear things up with Garchomp. 1. it's a physical attacker, just by looking at its base stats. 130 Attack is better than 80 Special Attack. 2. It can't learn Dragon Dance at all. 3. Even if Garchomp does get Dragon Dance, your current move set isn't taking full advantage of the Attack boost it provides:
-Stealth Rock
-Outrage/Dragon Claw
-Earthquake
-Fire Blast/Swords Dance
Nature: Naive/Jolly
EVs: 252 Atk/4 SAtk/252 Spe
Item: Lum Berry/Leftovers
or
-Swords Dance
-Outrage/Dragon Claw
-Earthquake
-Stone Edge/Fire Fang
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb/Lum Berry
or
-Outrage
-Earthquake
-Stone Edge/Rock Slide
-Fire Blast/Dragon Claw
Nature: Naive/Jolly
EVs: 252 Atk/4 SAtk/252 Spe
Item: Choice Scarf
or
-Stealth Rock
-Dragon Tail
-Earthquake
-Fire Blast/Toxic
Nature: Impish
EVs: 252 HP/252 Def/4 SDef
Item: Rocky Helmet
Ability: Rough Skin
Goodra may have a wide move pool, but it should mainly stick to Special moves; the only physical moves worth using are Earthquake and Dragon Tail. Ice Beam is also redundant with Goodra's Dragon STAB:
-Draco Meteor/Dragon Pulse
-Fire Blast
-Thunderbolt/Earthquake
-Dragon Tail/Earthquake
Nature: Quiet/Sassy
EVs: 248 HP/252 SAtk/8 SDef
Item: Assault Vest
Ability: Gooey/Sap Sipper
Sylveon is only good with Pixilate + Hyper Voice, which needs Poke Transfer from Black 2/White 2:
-Wish
-Protect
-Hyper Voice
-Heal Bell/Calm Mind
Nature: Bold
EVs: 252 HP/216 Def/40 SDef
Item: Leftovers
Ability: Pixilate
or
-Hyper Voice
-Psyshock
-Shadow Ball
-Hidden Power (Fire/Ground)/Baton Pass
Nature: Modest
EVs: 244 HP/252 SAtk/12 Spe
Item: Choice Specs
Ability: Pixilate
Given Heatran's current set, it's best using Choice Specs or Choice Scarf. In either case, Fire Blast is the preferred Fire STAB because of its higher power over Lava Plume, which only sees use on defensive sets. Solar Beam only sees use on Sun teams; the recharge turn is debilitating outside of them:
-Fire Blast/Overheat
-Flash Cannon
-Stone Edge/Earth Power
-Flamethrower/Fire Blast
Nature: Modest
EVs: 252 SAtk/4 SDef/252 Spe
Item: Choice Scarf/Choice Specs
Talonflame should run Adamant as opposed to Jolly, since Gale Wings is redundant with its high Speed. It's also not that strong, tbh, as it only has 81 base Attack and most of its power comes from the high base power of Brave Bird. It could also use Roost somewhere:
-Swords Dance
-Flare Blitz
-Brave Bird
-Roost
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb/Sharp Beak/Sky Plate
Ability: Gale Wings
or
-Flare Blitz
-Brave Bird
-U-turn
-Roost/Tailwind
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Sharp Beak/Sky Plate/Choice Band
Ability: Gale Wings
or
-Bulk Up
-Brave Bird
-Roost
-Taunt/Will-o-Wisp
Nature: Careful
EVs: 248 HP/8 Def/252 SDef
Item: Leftovers
Ability: Gale Wings
Dragalge is mediocre right now, since Adaptability isn't released. Don't bother with it.
Volcarona is best played as a bulky Quiver Dancer, since the offensive version has a tendency to get revenge killed more easily:
-Quiver Dance
-Bug Buzz
-Fiery Dance
-Roost
Nature: Bold
EVs: 248 HP/192 Def/68 Spe
Item: Leftovers
Ability: Flame Body
Don't bother with Ancient Power on Togekiss. Outside of hitting Talonflame and Charizard Y, it's useless and both are crippled by Thunder Wave anyways:
-Thunder Wave
-Air Slash
-Heal Bell/Defog/Aura Sphere/Flamethrower
-Roost
Nature: Calm/Bold
EVs: 248 HP/8 Def/252 SDef (Calm) or 248 HP/252 Def/8 SDef (Bold)
Item: Leftovers
Ability: Serene Grace
or
-Nasty Plot
-Air Slash
-Aura Sphere/Dazzling Gleam/Flamethrower/Heal Bell
-Roost
Nature: Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Leftovers/Lum Berry
Ability: Serene Grace
Jolly is a terrible nature for Gengar, since it wastes away its good Special Attack. Hypnosis + Dream Eater is also very unreliable because the moment you put an opposing Pokemon to sleep, there's a good chance it'll switch out, making Dream Eater useless on the switch-in:
-Shadow Ball
-Sludge Bomb
-Focus Blast/Thunderbolt
-Destiny Bond
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb
or
-Substitute
-Shadow Ball
-Will-o-Wisp
-Disable/Sludge Bomb/Taunt
Nature: Timid
EVs: 28 HP/148 SAtk/80 SDef/252 Spe
Item: Black Sludge
Tyrantrum faces competition from Mega Tyranitar as an attacker, especially Dragon Dance variants. It also faces competition from other OU Dragons, like Charizard X, Dragonite, and even Salamence and Haxorus. Don't bother.
I did enjoy using Trevenant for a time, but it's not viable enough in OU, since Bisharp (and other Dark Pokemon) is everywhere. But if you want to use it, it has to be played defensively; offensive sets are outclassed by Aegislash and Gengar:
-Horn Leech
-Earthquake/Rock Slide
-Will-o-Wisp
-Rest
Nature: Impish
EVs: 252 HP/180 Def/76 Spe
Item: Leftovers/Lum Berry
Ability: harvest
or
-Horn Leech
-Shadow Claw/Leech Seed
-Will-o-Wisp
-Protect
Nature: Careful
EVs: 248 HP/16 Def/244 SDef
Item: Sitrus Berry
Ability: Harvest
or
-Substitute
-Leech Seed
-Will-o-Wisp
-Phantom Force
Nature: Impish
EVs: 252 HP/180 Def/76 Spe
Item: Sitrus Berry
Ability: Harvest
Note that Mega Lucario is banned to Ubers. If this is still Battle Spot or Wi-Fi, Lucarionite is okay:
-Swords Dance
-Close Combat
-Extreme Speed
-Iron Tail/Crunch/Earthquake/Ice Punch
Nature: Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb/Lucarionite
or
-Nasty Plot
-Aura Sphere
-Flash Cannon
-Shadow Ball/Dark Pulse/Vacuum Wave
Nature: Timid
EVs: 4 Def/252 SAtk/252 Spe
Item: Lucarionite
Ability: Inner Focus/Steadfast
Rayquaza is an Uber, so you're best off not using them against people who don't like playing Ubers. Deoxys' Defense and Speed forms, on the other hand, are safe to use:
Defense:
-Stealth Rock
-Spikes
-Taunt
-Thunder Wave
Nature: Bold
EVs: 248 HP/72 Def/188 Spe
Item: Mental Herb
or
-Stealth Rock/Spikes
-Taunt
-Seismic Toss/Night Shade
-Recover
Nature: Bold
EVs: 252 HP/244 Def/12 Spe
Item: Leftovers
Speed:
-Stealth Rock
-Spikes
-Taunt
-Superpower/Magic Coat
Nature: Impish/Bold
EVs: 252 HP/252 Def/4 SDef
Item: Rocky Helmet/Focus Sash
or
-Reflect
-Light Screen
-Stealth Rock
-Taunt
Nature: Timid/Jolly
EVs: 252 HP/4 Def/252 Spe
Item: Light Clay
or
-Psycho Boost
-Low Kick/Superpower
-Ice Beam
-Stealth Rock/Knock Off
Nature: Naive
EVs: 20 Atk/252 SAtk/236 Spe
Item: Life Orb
As for a team, a team of Mega Tyranitar/Talonflame/Speed Deoxys/Excadrill/Sylveon/Garchomp would suffice.
Excadrill sets if you're wondering:
-Earthquake
-Iron Head
-Rapid Spin
-Rock Slide/Stealth Rock
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Leftovers/Air Balloon
Ability: Mold Breaker
or
-Earthquake
-Iron Head
-Rock Slide
-Rapid Spin
Nature: Adamant/Jolly
EVs: 252 Atk/4 Def/252 Spe (Choice Scarf) or 120 HP/136 Atk/252 SDef (Assault Vest; Adamant only)
Item: Choice Scarf/Assault Vest
Ability: Mold Breaker
I'll do the other Pokemon on your list some other time.
