I did a banlist that took me a lot of time.
After doing that list, I thought to myself "a EX-on extended format would be way easier to maintain". Less rules compatibility problems, and a really smaller banlist...
So because it is Unlimited, obviously it is a long list, and only playtesting would make a good banlist.
But the problem at the moment is that the battles can't really do more than one turn (I mean the second player must be able to play, not being locked), so you have to make a basic banlist to at least prevent this from happening.
The following cards should be banned no matter what, because :
1) They win the game on Turn 1
2) They allow to draw or search in deck too easily (thus allowing a Turn 1)
3) They're just plain broken and go against some basic principles of Pokémon
Computer Search (Base Set) (search in deck, combo with discard)
Lass (Base Set) (turn 1 BAM once I set up I remove all of your TSS)
Scoop Up (Base Set) (stupid combo with everything)
Super Energy Removal (Base Set) (NO ! )
Prof Oak (Base Set) (draw seven with a Trainer, all is said)
Energy Removal (Base Set) (NO !² )
Aerodactyl (Fossil) (combo with Aggron EX and Dark Vileplume, win turn 1)
Dark Vileplume (Team Rocket) (turn 1 no more TSS until the end of the game)
Erika (Gym Heroes) (draw waaaaay too easily)
Misty's Wrath (Gym Heroes) (draw way too easily, combo with discard)
The Rocket's Trap (Gym Heroes) (turn one you have no hand left)
Chaos Gym (Gym Challenge) (turn one I set up I play Chaos Gym)
Slowking (Neo Genesis) (turn 1 you cannot play TSS)
Bill's Teleporter (Neo Genesis) (draw way too easily)
Jolteon Star (EX Power Keepers) (turn one you win without attacking)
Umbreon Star (POP Series 5) (turn one you have no hand left)
Forretress (Legends Awakened) (turn 1 win by attaching a lot of energy cards)
Uxie (Legends Awakened) (I draw, Scoop Up I draw, Briney I draw, Seeker I draw...)
Sableye (Stormfront) (no brainer)
Poké Drawer + (Stormfront) (let's seek any two cards for free !)
Crobat G (Platinum) (turn one you win without attacking)
Broken Time Space (Platinum) (Kingdra Prime / Dark Golbat / Crobat, and T1 combos)
Seeker (Triumphant) (Porygon2 Seeker... And stupid combos like Scoop Up)
Limited (1 copy per deck) :
Blaine's Quiz #2 (Gym Challenge) (draw too easily)
Lt. Surge's Treaty (Gym Heroes) (draw too easily)
Card-Flip Game (Neo Genesis) (draw too easily)
Porygon2 (Great Encounters) (combo with Seeker, and way too abusable)
Pokédex HANDY910is (Diamond and Pearl) (draw too easily)
And here is a veeeeeeryyyyyyy looooong list of "I don't know what to do with those" cards :
The following cards are at least worth noticing, I don't know what to do with those :
Gust of Wind (Base Set) (combo with Murkrow, and too powerful overall)
Item Finder (Base Set) (if you ban broken trainers and draw trainers maybe it's allowable)
Pokémon Center (Base Set) (heal everyone !)
Pokémon Flute (Base Set) (without heavy discard turn 1 it's allowable)
Mr. Fuji (Fossil) (another card to reuse "comes into play" effects)
Dark Golbat (Team Rocket) (if you allow BTS, ban this)
Rocket's Sneak Attack (Team Rocket) (if reusable with Item Finder / Junk Arm, I'd ban it)
Impostor Oak's Revenge (Team Rocket) (if discard trainers / powers are allowed, I'd ban it)
Goop Gas Attack (Team Rocket) (shut down all powers / bodies / abilities until opponent's turn)
Erika's Dratini (Gym Heroes) (If you allow Aerodactyl + a trainer lock, ban it)
Erika's Perfume (Gym Heroes) (don't mind if I fill up your bench ?)
Secret Mission (Gym Heroes) (draw + discard but no card advantage)
Energy Flow (Gym Heroes) (if you allow LA Forretress, ban it)
Narrow Gym (Gym Heroes) (that's a Scoop Up)
Sabrina's Gaze (Gym Heroes) (draw trainer but no card advantage)
Trash Exchange (Gym Heroes) (stupid combos to be done)
Misty's Wish (Gym Challenge) (draw 1 card everytime after Azelf used Time Walk)
Murkrow (Neo Genesis) (turn 1 GoW and trainer lock, your active is stucked forever), bar Cyclone / Warp Energy)
Double Gust (Neo Genesis) (Gust of Wind like)
Super Scoop Up (Neo Genesis) (abusable "comes into play" effects)
Hyper Devolution Spray (Neo Discovery) (if you allow BTS, ban this)
Dark Crobat (Neo Destiny) (if you allow BTS, ban this)
Pokémon Personality Test (Neo Destiny) (draw trainer usable with Dark Pokémon)
Mail from Bill (Neo Destiny) (draw until you have 4 cards in hand, maybe abusable)
Dark Ivysaur (BEST Promos) (Gust of Wind like)
Espeon (Aquapolis) (if you allow LA Forretress, ban it ASAP)
Suicune (Aquapolis) (combo with Rain Dance / Trash Exchange and or LA Kingdra)
Boost Energy (Aquapolis) (turn 1 Drifblim UD)
Beedrill (Skyridge) (You're paralysed, Devolutionary you're paralysed...)
Gyarados (Skyridge) (Energy Removal in power, but only on the active)
Ancient Ruins (Skyridge) (draw 1 card)
Desert Shaman (Skyridge) (Judge, if there are discard trainers / powers, I'd ban it)
Oracle (Skyridge) (take two cards, put them on top, and draw them with a draw trainer)
Pokémon Reversal (EX Ruby Sapphire) (GoW with a coin flip)
Mr Briney's Compassion (EX Dragon) (see Scoop Up, but it's a Supporter)
Pidgeot (EX FireRed LeafGreen) (Search any card once per turn)
Electrode ex (EX FireRed LeafGreen) (Abusable with Rocket's Admin / N)
Rocket's Admin (EX Team Rocket's Return) (combo with Electrodes early game)
Swoop! Teleporter (EX Team Rocket's Return) (strong, combo with Jirachi DX)
Milotic (EX Hidden Legends) (Heal everyone !)
Jirachi (EX Deoxys) (combo with Swoop! Teleporter)
Shedinja (EX Deoxys) (chain of Shedinjas never giving a prize is possible in Unlimited)
Crobat ex (EX Deoxys) (if you allow BTS, ban this)
Ursaring (EX Unseen Forces) (If you allow Aerodactyl + a trainer lock, ban it)
Aipom (EX Unseen Forces) (effective draw)
Espeon ex (EX Unseen Forces) (if you allow BTS, ban this)
Umbreon ex (EX Unseen Forces) (Gust of Wind like)
Jolteon ex (EX Delta Species) (if you allow BTS, ban this)
Aquali ex (EX Delta Species) (Judge, if there are discard trainers / powers, I'd ban it)
Giant Stump (EX Legend Maker) (strong but it's not a Scoop Up like Narrow Gym. Combo with Erika's Perfume)
Holon Circle (EX Crystal Guardians) (you don't attack, you don't attack, you don't attack)
Aggron ex (EX Crystal Guardians) (If you allow Aerodactyl + a trainer lock, ban it)
Metagross ex (EX Power Keepers) (Judge, if there are discard trainers / powers, I'd ban it)
Luxray GL Lv X (Rising Rivals) (Gust of Wind like)
Kingdra (Unleashed) (if you allow BTS, ban this)
Judge (Unleashed) (if there are discard trainers / powers, I'd ban it)
Weavile (Undaunted) (if you allow BTS, ban this or your opponent has no cards in hand left)
Junk Arm (Triumphant) (See Item Finder)
N (Emerging Powers) (Abusable with Electrodes)
Pokémon Catcher (Red Collection) (combo with Murkrow, and too powerful overall)
If anyone is brave enough to read all of this, please comment 'cause I'm probably not objective on some cards's strengths.