Egg Groups
Each Pokémon belongs to one or two egg groups (following Stadium 2's names). It can breed with other Pokémon from the groups it belongs too. Pokémon with unknown gender (Porygon foe example) can only breed with Ditto. However, Pokémon in the "Unbreedable" group are unable to produce eggs, neither with other Pokémon from the same group nor with Ditto. Ditto cannot breed with Ditto. Also have in mind that some Pokémon may not appear in some versions. Hint: In order to find in which other group a Pokémon belongs to, do Ctrl+F and search for the Pokémon you want.
Monster
Abomasnow, Aggron, Ampharos, Aron, Bastiodon, Bayleef, Blastoise, Bulbasaur, Charizard, Charmander, Charmeleon, Chikorita, Cranidos, Croconaw, Cubone, Exploud, Feraligatr, Flaaffy, Gabite, Garchomp, Gible, Grotle, Grovyle, Ivysaur, Kangaskhan, Lairon, Lapras, Larvitar, Lickilicky, Lickitung, Loudred, Mareep, Marowak, Marshtomp, Meganium, Mudkip, Nidoking, Nidoran♀, Nidoran♂, Nidorino, Pupitar, Rampardos, Rhydon, Rhyhorn, Rhyperior, Sceptile, Shieldon, Slowbro, Slowking, Slowpoke, Snorlax, Snover, Squirtle, Swampert, Torterra, Totodile, Treecko, Tropius, Turtwig, Tyranitar, Venusaur, Wartortle, Whismur
Water 1
Azumarill, Bibarel, Bidoof, Blastoise, Buizel, Clamperl, Corphish, Corsola, Crawdaunt, Croconaw, Delibird, Dewgong, Dragonair, Dragonite, Dratini, Empoleon, Feebas, Feraligatr, Floatzel, Gastrodon, Golduck, Gorebyss, Horsea, Huntail, Kabuto, Kabutops, Kingdra, Lapras, Lombre, Lotad, Ludicolo, Manaphy, Mantine, Marill, Marshtomp, Masquerain, Milotic, Mudkip, Octillery, Omanyte, Omastar, Pelipper, Phione, Piplup, Politoed, Poliwag, Poliwhirl, Poliwrath, Prinplup, Psyduck, Quagsire, Relicanth, Remoraid, Seadra, Sealeo, Seel, Shellos, Slowbro, Slowking, Slowpoke, Spheal, Squirtle, Surskit, Swampert, Totodile, Walrein, Wartortle, Wingull, Wooper
Bug
Ariados, Beautifly, Beedrill, Burmy, Butterfree, Cascoon, Caterpie, Combee, Drapion, Dustox, Flygon, Forretress, Gligar, Gliscor, Heracross, Illumise, Kakuna, Kricketot, Kricketune, Ledian, Ledyba, Masquerain, Metapod, Mothim, Nincada, Ninjask, Paras, Parasect, Pineco, Pinsir, Scizor, Scyther, Shuckle, Silcoon, Skorupi, Spinarak, Surskit, Trapinch, Venomoth, Venonat, Vespiquen, Vibrava, Volbeat, Weedle, Wormadam, Wormadam (Ground), Wormadam (Steel), Wurmple, Yanma, Yanmega
Flying
Aerodactyl, Altaria, Chatot, Crobat, Dodrio, Doduo, Farfetch'd, Fearow, Golbat, Honchkrow, Hoothoot, Murkrow, Natu, Noctowl, Pelipper, Pidgeot, Pidgeotto, Pidgey, Skarmory, Spearow, Staraptor, Staravia, Starly, Swablu, Swellow, Taillow, Togekiss, Togetic, Wingull, Xatu, Zubat
Ground
Absol, Aipom, Ambipom, Ampharos, Arbok, Arcanine, Bibarel, Bidoof, Blaziken, Buizel, Buneary, Camerupt, Chimchar, Combusken, Cyndaquil, Delcatty, Delibird, Dewgong, Diglett, Donphan, Dugtrio, Dunsparce, Eevee, Ekans, Electrike, Empoleon, Espeon, Exploud, Farfetch'd, Flaaffy, Flareon, Floatzel, Furret, Girafarig, Glaceon, Glameow, Golduck, Granbull, Growlithe, Grumpig, Hippopotas, Hippowdon, Houndoom, Houndour, Infernape, Jolteon, Kecleon, Leafeon, Linoone, Lopunny, Loudred, Lucario, Luxio, Luxray, Mamoswine, Manectric, Mankey, Mareep, Mawile, Meowth, Mightyena, Miltank, Monferno, Nidoking, Nidoran♀, Nidoran♂, Nidorino, Ninetales, Numel, Nuzleaf, Pachirisu, Persian, Phanpy, Pikachu, Piloswine, Piplup, Ponyta, Poochyena, Primeape, Prinplup, Psyduck, Purugly, Quagsire, Quilava, Raichu, Rapidash, Raticate, Rattata, Rhydon, Rhyhorn, Rhyperior, Sandshrew, Sandslash, Sealeo, Seedot, Seel, Sentret, Seviper, Shiftry, Shinx, Skitty, Skuntank, Slaking, Slakoth, Smeargle, Sneasel, Snubbull, Spheal, Spinda, Spoink, Stantler, Stunky, Swinub, Tauros, Teddiursa, Torchic, Torkoal, Typhlosion, Umbreon, Ursaring, Vaporeon, Vigoroth, Vulpix, Wailmer, Wailord, Walrein, Weavile, Whismur, Wooper, Zangoose, Zigzagoon
Fairy
Azumarill, Blissey, Breloom, Castform, Chansey, Cherrim, Cherubi, Clefable, Clefairy, Delcatty, Froslass, Glalie, Granbull, Hoppip, Jigglypuff, Jumpluff, Manaphy, Marill, Mawile, Minun, Pachirisu, Phione, Pikachu, Plusle, Raichu, Roselia, Roserade, Shroomish, Skiploom, Skitty, Snorunt, Snubbull, Togekiss, Togetic, Wigglytuff
Plant
Abomasnow, Bayleef, Bellossom, Bellsprout, Breloom, Bulbasaur, Cacnea, Cacturne, Carnivine, Cherrim, Cherubi, Chikorita, Exeggcute, Exeggutor, Gloom, Grotle, Hoppip, Ivysaur, Jumpluff, Lombre, Lotad, Ludicolo, Meganium, Nuzleaf, Oddish, Paras, Parasect, Roselia, Roserade, Seedot, Shiftry, Shroomish, Skiploom, Snover, Sunflora, Sunkern, Tangela, Tangrowth, Torterra, Tropius, Turtwig, Venusaur, Victreebel, Vileplume, Weepinbell
Humanshape
Abra, Alakazam, Buneary, Cacnea, Cacturne, Chimchar, Croagunk, Drowzee, Electabuzz, Electivire, Hariyama, Hitmonchan, Hitmonlee, Hitmontop, Hypno, Illumise, Infernape, Jynx, Kadabra, Lopunny, Lucario, Machamp, Machoke, Machop, Magmar, Magmortar, Makuhita, Medicham, Meditite, Monferno, Mr. Mime, Sableye, Spinda, Toxicroak, Volbeat
Water 3
Anorith, Armaldo, Cloyster, Corphish, Corsola, Cradily, Crawdaunt, Drapion, Kabuto, Kabutops, Kingler, Krabby, Lileep, Omanyte, Omastar, Shellder, Skorupi, Starmie, Staryu, Tentacool, Tentacruel
Mineral
Baltoy, Beldum, Bronzong, Bronzor, Claydol, Electrode, Froslass, Geodude, Glalie, Golem, Graveler, Lunatone, Magnemite, Magneton, Magnezone, Metagross, Metang, Nosepass, Onix, Porygon, Porygon-Z, Porygon2, Probopass, Shedinja, Snorunt, Solrock, Steelix, Sudowoodo, Voltorb
Inteterminate
Banette, Castform, Chimecho, Drifblim, Drifloon, Dusclops, Dusknoir, Duskull, Gallade, Gardevoir, Gastly, Gastrodon, Gengar, Grimer, Gulpin, Haunter, Kirlia, Koffing, Magcargo, Misdreavus, Mismagius, Muk, Ralts, Rotom, Shellos, Shuppet, Slugma, Spiritomb, Swalot, Weezing, Wobbuffet
Water 2
Barboach, Carvanha, Chinchou, Finneon, Goldeen, Gyarados, Lanturn, Lumineon, Luvdisc, Magikarp, Octillery, Qwilfish, Relicanth, Remoraid, Seaking, Sharpedo, Wailmer, Wailord, Whiscash
Ditto
Ditto
Dragon
Altaria, Arbok, Bagon, Charizard, Charmander, Charmeleon, Dragonair, Dragonite, Dratini, Ekans, Feebas, Gabite, Garchomp, Gible, Grovyle, Gyarados, Horsea, Kingdra, Magikarp, Milotic, Salamence, Sceptile, Seadra, Seviper, Shelgon, Swablu, Treecko
No Eggs
Arceus, Articuno, Azelf, Azurill, Bonsly, Budew, Celebi, Chingling, Cleffa, Cresselia, Darkrai, Deoxys, Deoxys ATK, Deoxys DEF, Deoxys SPD, Dialga, Elekid, Entei, Giratina, Groudon, Happiny, Heatran, Ho-oh, Igglybuff, Jirachi, Kyogre, Latias, Latios, Lugia, Magby, Mantyke, Mesprit, Mew, Mewtwo, Mime Jr., Moltres, Munchlax, Nidoqueen, Nidorina, Palkia, Pichu, Raikou, Rayquaza, Regice, Regigigas, Regirock, Registeel, Riolu, Shaymin, Smoochum, Suicune, Togepi, Tyrogue, Unown, Uxie, Wynaut, Zapdos