Pokémon evolutions by trading

This is a list of Pokémon that evolve by trading. The classic four evolutions (Alakazam, Machoke, Graveler and Gengar) from Red/Blue/Yellow evolve only by trading, while most Pokémon from later generations require an item to be held in addition.

This information applies to any games that feature both Pokémon from the chain, so for example in Generation 1 the evolution chain with Steelix doesn't exist.

The Pokémon

Evolving from
Evolving to
Hold item/condition
Poliwhirl Poliwhirl → Politoed Politoed ( Kings Rock)
Kadabra Kadabra → Alakazam Alakazam (Trade)
Machoke Machoke → Machamp Machamp (Trade)
Graveler Graveler → Golem Golem (Trade)
Alolan Graveler Graveler
Alolan Graveler 		→ Alolan Golem Golem
Alolan Golem 		(Trade)
Slowpoke Slowpoke → Slowking Slowking ( Kings Rock)
Haunter Haunter → Gengar Gengar (Trade)
Onix Onix → Steelix Steelix ( Metal Coat)
Rhydon Rhydon → Rhyperior Rhyperior ( Protector)
Seadra Seadra → Kingdra Kingdra ( Dragon Scale)
Scyther Scyther → Scizor Scizor ( Metal Coat)
Electabuzz Electabuzz → Electivire Electivire ( Electirizer)
Magmar Magmar → Magmortar Magmortar ( Magmarizer)
Porygon Porygon → Porygon2 Porygon2 ( Upgrade)
Porygon2 Porygon2 → Porygon-Z Porygon-Z ( Dubious Disc)
Feebas Feebas → Milotic Milotic ( Prism Scale, or level up with max Beauty)
Dusclops Dusclops → Dusknoir Dusknoir ( Reaper Cloth)
Clamperl Clamperl → Huntail Huntail ( Deep Sea Tooth)
Clamperl Clamperl → Gorebyss Gorebyss ( Deep Sea Scale)
Boldore Boldore → Gigalith Gigalith (Trade)
Gurdurr Gurdurr → Conkeldurr Conkeldurr (Trade)
Karrablast Karrablast → Escavalier Escavalier (Trade with Shelmet)
Shelmet Shelmet → Accelgor Accelgor (Trade with Karrablast)
Spritzee Spritzee → Aromatisse Aromatisse ( Sachet)
Swirlix Swirlix → Slurpuff Slurpuff ( Whipped Dream)
Phantump Phantump → Trevenant Trevenant (Trade)
Pumpkaboo (Average Size) Pumpkaboo
Average Size 		→ Gourgeist (Average Size) Gourgeist
Average Size 		(Trade)