Generation I
Caterpie line and Weedle line
Sandshrew line and Ekans line
Alolan Sandshrew line and Alolan Vulpix line
Nidoran F line and Nidoran M line
Vulpix line and Growlithe line
Oddish line and Bellsprout line
Meowth line and Mankey line
Magnemite line and Voltorb line
Hitmonlee and Hitmonchan
Shellder line and Staryu line
Scyther and Pinsir
Electabuzz and Magmar
Blaze Breed Paldean Tauros and Aqua Breed Paldean Tauros
Omanyte line and Kabuto line
Generation II
Ledyba line and Spinarak line
Espeon and umbreon
Misdreavus line and Murkrow line
Gligar line and Sneasel line
Teddiursa line and Phanpy line
Mantine and Skarmory
Lugia and Ho-oh
Generation III
Poochyena line and Zigzagoon line
Beautifly and Dustox
Lotad line and Seedot line
Taillow line and Wingull line
Sableye and Mawile
Plusle and Minun
Volbeat and Illumise
Carvanha line and Numel line
Zangoose and Seviper
Lunatone and Solrock
Lileep line and Anorith line
Shuppet line and Duskull line
Latias and Latios
Kyogre and Groudon
Generation IV
Cranidos line and Shieldon line
Glameow line and Stunky line
Leafeon and Glaceon
Dialga and Palkia
Cresselia and Darkrai
Generation V
Throh and Sawk
Cottonee line and Petilil line
Tirtouga line and Archen line
Gothita line and Solosis line
Karrablast line and Shelmet line
Rufflet line and Vullaby line
Heatmor and Durant
Tornadus and Thundurus
Zekrom and Reshiram
Generation VI
Spritzee line and Swirlix line
Skrelp line and Clawitzer line
Tyrunt line and Amaura line
Xerneas and Yveltal
Generation VII
Oranguru and Passimian
Turtonator and Drampa
Solgaleo and Lunala
Buzzwole and Pheromosa
Celesteela and Kartana
Stakataka and Blacephalon
Generation VIII
Flapple and Appletun
Hattena and Impidimp
Cursola and Sirfetch'd
Stonjourner and Eiscue
Zacian and Zamazenta
Generation IX
Amarouge and Ceruledge
Great Tusk and Iron Treads
Scream Tail and Iron Bundle
Brute Bonnet and Iron Hands
Flutter Mane and Iron Jugulis
Slither Wing and Iron Moth
Sandy Shocks and Iron Thorns
Roaring Moon and Iron Valiant
Koraidon and Miraidon
Walking Wake and Iron Leaves
Gouging Fire and Iron Boulder
Raging Bolt and Iron Crown
Cross-generational
Alolan Rattata line and Yungoos line
Paras and Morelull
Magikarp and Feebas
Pinsir and Heracross
Tauros and Miltank
Houndour and Electrike
Surskit and Dewpider
Pokemon counterparts (Bulbapedia)
Hope I helped!
