Evolutionary families ordered by their earliest appearing member in the National Pokedex.
Bulbasaur / Ivysaur / Venusaur
Butterfree
Beedrill
Pichu / Pikachu / Raichu
Cleffa/ Clefairy / Clefable
Igglybuff / Jigglypuff / Wigglytuff
Oddish / Gloom / Vileplume / Bellossom
Paras / Parasect
Venonat / Venomoth
Meowth / Persian
Psyduck / Golduck
Abra / Kadabra / Alakazam
Bellsprout / Weepinbell / Victreebel
Slowpoke / Slowbro / Slowking
Magnemite / Magneton / Magnezone
Drowzee / Hypno
Voltorb / Electrode
Exeggcute / Exeggutor
Koffing / Weezing
Happiny / Chansey / Blissey
Tangela / Tangrowth
Horsea / Seadra
Staryu / Starmie
Mime Jr. / Mr. Mime
Smoochum / Jynx
Elekid / Electabuzz / Electivire
Jolteon / Espeon / Umbreon / Leafeon
Porygon / Porygon2 / Porygon-Z
Zapdos
Mewtwo
Mew
Chikorita / Bayleef / Meganium
Ledyba / Ledian
Spinarak / Ariados
Chinchou / Lanturn
Togepi / Togetic / Togekiss
Natu / Xatu
Mareep / Flaaffy / Ampharos
Hoppip / Skiploom / Jumpluff
Sunkern / Sunflora
Yanma / Yanmega
Wooper / Quagsire
Misdreavus / Mismagius
Girafarig
Shuckle
Skarmory
Stantler
Raikou
Entei
Lugia
Ho-oh
Celebi
Treecko / Grovyle / Sceptile
Beautifly / Dustox
Lotad / Lombre / Ludicolo
Seedot / Nuzleaf / Shiftry
Ralts / Kirlia / Gardevoir / Gallade
Surskit / Masquerain
Shroomish / Breloom
Nincada / Ninjask / Shedinja
Skitty / Delcatty
Sableye
Meditite / Medicham
Electrike / Manectric
Plusle
Minun
Volbeat
Illumise
Budew / Roselia / Roserade
Spoink / Grumpig
Spinda
Cacnea / Cacturne
Lunatone
Solrock
Baltoy / Claydol
Lileep / Cradily
Castform
Kecleon
Shuppet / Banette
Duskull / Dusclops / Dusknoir
Tropius
Chingling / Chimecho
Absol
Snorunt / Glalie / Froslass
Metang / Metagross
Latias
Latios
Jirachi
Deoxys (all forms)
Turtwig / Grotle / Torterra
Kricketune
Shinx / Luxio / Luxray
Wormadam / Mothim
Vespiquen
Pachirisu
Cherubi / Cherrim
Gastrodon
Drifloon / Drifblim
Glameow / Purugly
Bronzor / Bronzong
Spiritomb
Skorupi / Drapion
Carnivine
Finneon / Lumineon
Snover / Abomasnow
Rotom
Uxie
Mesprit
Azelf
Dialga
Cresselia
Manaphy
Darkrai
Shaymin (both forms)
Source: Ctrl + f "Flash" on this Explorers of Sky movepool database
