Baby & Juvenile pokemon-
Pichu, Igglybuff, Cleffa, Smoochum, Elekid, Tyrouge, Magby, Azurill, Preevee, Dauberan, Wurmple, Silcoon, Cascoon, Seedot, Sunkern, Caterpie, Weedle, Kakuna, Metapod, Exeggcute, Wooper, Poliwag, Phanpy, Teddiursa, Togepi, Pupitar, Mudkip, Shedinja, Wishmur, Aron, Trapinch, Wynaut, Snorunt, Spheal, Beldum, Lateon, Bunnut, Furflit, Wailmer, Lotad, Dungrub, Pincit, Chikapo, Dibble, Jablet, Chea, Soarbet, Squirmseed, Numbwog, Lilthing, Lurkit, Pipgiggle, Merriwish.

Mechanical-
Magnemite, Magneton, Voltorb, Electrode, Porygon, Porygon2

Ghost-
Ghastly, Haunter, Gengar, Misdreavus, Sableye, Shuppet, Banette, Duskull, Dusclops, Soloa, Dreadwood, Watchly, Gazer, Barkhest.

Other Non-Breeding: Unown

--Breeding--

Asexual:
Pokemon listed here do not need a breeding partner & produce young via 'Budding' process or self-fertilization.
Grimer, Muk, Swalot, Gulpin, Slugma, Magcargo, Koffing, Weezing, Ditto (to make another ditto), Castform

Gamete Reproduction:
Pokemon listed here require a partner, but minimal physical contact. Fertilization occurs mostly outside the body.

Sea Life -
Shellder, Cloyster, Clamperl, Staryu, Starmie, Tenticool, Tentacruel, Krabby, Kingler, Ominite, Omastar, Kabuto, Kabutops, Corosola, Octillery, Corphish, Crawdaunt, Lipsnap, Uppercutlet, Kayoh.

Fish like-
Magikarp, Horsea, Seadra, Goldeen, Seaking, Chinchou, Lanturn, Quilfish, Remoraid, Octillery, Carvanha, Sharpedo, Barboach, Wiscash, Feebas, Relicanth, Luvdisc, Mantine, Kingdra, Milotic, Huntail, Gorebyss, Glassea, Oddesea, Leopisces, Enochian, Ichthynaut, Pokeet, Stabeet, Swishkebab.

Amphibian like-
Poliwhirl, Poliwrath, Pilotoed, Quagsire, Marshtomp, Swampert, Lombre, Ludicolo, Paranox, Wattnewt.

Plant-
(in cases such as Bulbasaurs, the pokemon is a pollen donor.)
Oddish, Gloom, Vileplume, Paras, Parasect, Bellsprout, Weepinbell, Victreebel, Exeggcutor,Tangela, Bulbasaur, Ivysaur, Venasaur, Chikorita, Bayleef, Meganium, Bellossom, Hoppip, Skiploom, Jumpluff, Sunflora, Treeko, Grovyle, Sceptile, Lotad, Lombre, Ludicolo, Nuzleaf, Shiftry, Shroomish, Breloom, Roselia, Cacnea, Cacturne, Lileep, Cradily, Tropius, Hopleaf, Stempede, Ginnaginna, Ginnagura, Skullbulb, Chucklefluff, Lafflora.

Sexual Reproduction:
Pokemon listed here require a physical partner. Sub-groups of size denote success rate of female fertility as well as better over all compatibility w/ in the over all group but, does not restrict breeding between sizes in the over all group.

Mineral-
Geodude, Graveler, Golem, Onix, Steelix, Sudowoodo, Larvitar, Tyranitar, Nosepass, Lunatone, Solrock, Baltoy, Claydol, Glalie, Metang, Metagross, Regirock, Regice, Registeel.

Bug-
Butterfree, Beedrill, Paras, Parasect, Venonat, Venomoth, Scyther, Pinsir, Ledyba, Ledian, Spinarak, Ariados, Yanma, Pineco, Forretress, Scizor, Shuckle, Heracross, Beautifly, Dustox, Surskit, Masquerain, Nincada, Ninjask, Volbeet, Illuminise, Anorith, Armaldo, Scataluna, Scaraburn, Skuddloar.

Reptile like-
--(Small, low chance of successful breeding)
Bulbasaur, Charmander, Squirtle, Chikorita, Totodile, Ekans, Dratini, Treeko, Bagon, Larvitar, Torkoal, Zaplotyl, Flitling.
--(Medium, average chance of successful breeding)
Lickitung, Kecleon, Seviper, Ivysaur, Charmeleon, Wartortle, Bayleef, Croconaw, Arbok, Dragonair, Grovyle, Shelgon, Dunsparce, Zapguana, Wispwing.
--(Large, good healthy breeding)
Venasaur, Charizard, Blastiose, Meganium, Feraligatr, Dragonite, Tropius, Salamence, Tyranitaur, Sceptile, Onix, Lapras, Aerodactyl, Steelix, Groudon, Zaptor.

Dragon like-
Charizard, Dragonair, Dragonite, Salamence, Kingdra, Lapras, Flygon, Gyarados, Altaria, Latias , Latios, Lugia, Virbrava, Flygon, Milotic, Kyogre, Groudon, Rayquaza, Zaptor.

Bird-
(Smaller)
Pidgey, Spearow, Psyduck, Farfatch'd, Hoothoot, Togetic, Natu, Murkrow, Delibird, Torchic, Tailow, Swellow, Wingull, Swablu, Hyron, Flitterbee, Flutterby, P'Tooi.
(Larger)
Pidgeotto, Pidgeot, Fearow, Doduo, Dodrio, Magmar, Articuno, Zapdos, Moltres, Noctowl, Xatu, Skarmory, Ho-oh, Darkius, Combusken, Blaziken, Pelipper, Altaria, Psycat, Leogle, Kakapeat, Ayechea, Kingchea.

Faerie-
Wobuffet, Clefairy, Clefable, Jigglypuff, Wigglytuff, Chansey, Blissey, Togetic, Celibi, Chucklefluff, Lafflora, Merrimint, Merryule.

Rodent like-
(Small)
Rattata, Pikachu, Sandshrew, Nidoran-f, Nidoran-m, Diglett, Marill, Plusle, Minun, RF Nidoran-f, RF Nidoran-m, Otachiran, Ginnaginna, Ginnagura, Auburntle, Glyptodillo,
(Large)
Raticate, Raichu, Sandslash, Nidorina, Nidorino, Dugtrio, Azumarill, Spinda, RF Nidorina, RF Nidorino, Ikarichu, Ootachirino, Whumpbat(M), Burnaudle, Burntoodle, Armordon.

Field -
Ponyta, Rapidash, Drowsee, Rhyhorn, Tauros, Mareep, Flaaffy, Ampharos, Girafarig, Swinub, Piloswine, Donphan, Stantler, Miltank, Lairon, Aggron, Numel, Camerupt, Spoink, Grumpig, Nidoking, Rydon, Aggron, RF Nidoking, Nidoqueen, RF Nidoqueen, Stempede, Ootaranknight, Kangaskhan(M), Kangasblade, Armordon.

Monster like-
Nidoqueen, Nidoking, Golduck, Rhydon, Ampharos, Slowking, Blaziken, Exploud, Aggron, Rootachi, RF Nidoqueen, RF Nidoking, Ootaranknight, Kangasblade, Ichthynaut.

Feline-
Zangoose, Skitty, Delcatty, Sneasel, Meowth, Persain, Mew, Mewtwo, Denkiko, Raikou, Entei, Kajiko, Psycat, Talion, Leogle.

Simian Like-
Mankey, Primeape, Abra, Kadabra, Alakazam, Machop, Machoke, Machamp, Hypno, Hitmonlee, Hitmonchan, Mr. Mime, Jynx, Magmar, Aipom, Hitmontop, Electabuzz, Mewtwo, Smeargle, Combusken, Blaziken, Slakoth, Vigaroth, Slaking, Ralts, Kirlia, Gardevoir, Nuzleaf, Shiftry, Meditite, Medicham, Loudred, Makuhita, Hariyama, Mawile, Makimur, Maximur, Reximur, Galagost, Grymlin, Ghoulaiy, Painterrior.

Canine-
(Small)
Vulpix, Growlithe, Eevee, Jolteon, Flareon, Espeon, Snubbul, Houndour, Electrike.
(Large)
Nintails, Arcanine, Vaporeon, Umbreon, Granbul, Houndoom, Smeargle, Entei, Suicune, Manectric, Absol, Kajiko, Frost, Eon, Florion-F, Florion-M, Painterrior, Lunarix, Lusseon.

Omnivor Mammal like-
(Small & Medium)
Cyndaqui, Quilava, Sentret, Zigzagoon, Poochyena, Furret, Sandshrew, Sandslash, Slowpoke, Cubone, Marowak, Linone, Mightyena, Spinda, Wade, Boogie, Kahuna, Greenet, Vyhienadon, Otachiran, Ootachirino, Derrible(M), Wallatree(M), Thylico(M), Burntoodle, Glyptodillo, Erinachiropt, Indigoyle,
(Large)
Typhlosion, Rootachi, Ursaring, Slowbro, Snorlax, Mewtwo, Zangoose, Sandspine, Ootaranknight, Thylico(M), Armordon.

Bat like-
Zubat, Gligar, Golbat, Crobat, Erinachiropt, Indigoyle.

Sea Mammal like-
Seel, Dewgong, Slowpoke, Slowbro, Slowking, Sealeo, Walrein, Wade, Boogie, Kahuna, Marluga, Marsopa.

---Exclusives (breed only with thier own kind)---
Chimecho: The breeding habits of this pokemon have yet to be observed, but it is know they will not breed w/ other pokemon, including ditto.

Marsupials:
Marsupial females have evolved a unique method of reproduction to cope with the rareity of males in thier species. Upon the rare chance of mating w/ a male, several embryos are produced. Only one is developed at at time, the remaining embryos are kept in a suspended state until the female is ready to rear another young. Many trainers have made the mistake of believing thier pokemon was impregnated by another species. This cannot happen. On a side, note, males of this category appear to be perfectly capable of breeding to some other pokemon species.
-Kangaskhan, Kangasblade, Derrible, Wallatree, Whumpbat, Thylico.

Wailord: Wailord only breed with thier own kind.

Flamanko: Breed only with thier own kind.

Oozlug: Breed only with thier own kind.