Each Pokémon has one or more egg groups, only Pokémon in the same egg groups may breed.
Groups:
(Names are clickable to see all Pokémons in the groups)
- Amorphous is connected to Fairy / Grass / Mineral / Water 1 and has 59 Pokémons in this egg group.
The egg group Amorphous has mostly pokémons that aren't based on real creatures,but they are instead shapeless blobs or gases. Like Ghost and Poison Pokémon.
- Bug is connected to Fairy / Grass / Human-Like / Mineral / Water 1 / Water 3 and has 79 Pokémons in this egg group.
The egg group Bug has pokémons that are based on mainly Bug types. There are very few Pokémon here also in a second group, and several do not learn egg moves.
- Dragon is connected to Field / Flying / Monster / Water 1 / Water 2 and has 52 Pokémons in this egg group.
The egg group Dragon has pokémons that are based on dragons. Less than half of the Pokémon in this group are Dragon type. Most of the Pokémon here belong to a second group.
- Fairy is connected to Amorphous / Bug / Field / Flying / Grass / Mineral / Water 1 and has 51 Pokémons in this egg group.
The egg group Fairy has pokémons that are mostly cute Pokémon, or Majestic in their appearance.
- Field is connected to Dragon / Fairy / Flying / Grass / Human-Like / Monster / Water 1 / Water 2 and has 233 Pokémons in this egg group.
The egg group Field is the largest egg group. As well as having many Ground type Pokémon, the Field group contains lots of land-based mammals and has the most diverse range of types. This makes for easy breeding of multiple moves.
- Flying is connected to Dragon / Fairy / Field / Water 1 / Water 3 and has 60 Pokémons in this egg group.
The egg group Flying has Pokémons that are mostly a bird-like appearance.
- Grass is connected to Amorphous / Bug / Fairy / Field / Human-Like / Mineral / Monster / Water 1 and has 68 Pokémons in this egg group.
The egg group Grass has Pokémon that are mostly some kind of plant.
- Human-Like is connected to Bug / Field / Grass and has 52 Pokémons in this egg group.
The egg group Human-Like has Pokémon that are bipedal, like humans. Most Fighting type Pokémon are in this group.
- Mineral is connected to Amorphous / Bug / Fairy / Grass and has 61 Pokémons in this egg group.
The egg group Mineral has Pokémons mostly based on inanimate objects, most are Rock and Steel type. The majority of Pokémon here are only in this group and many are genderless.
- Monster is connected to Dragon / Field / Grass / Water 1 and has 80 Pokémon in this egg group.
The egg group Monster are large, powerful beasts. It is one of the largest and most diverse groups. Many of the starters are in this group.
- Water 1 is connected to Amorphous / Bug / Dragon / Fairy / Field / Flying / Grass / Monster / Water 2 / Water 3 and has 95 Pokémons in this egg group.
The egg group Water 1 are generally amphibious (surviving in and out of water) Pokémon. All the water type starters are in this egg group.
- Water 2 is connected to Dragon / Field / Water 1 and has 26 Pokémons in this egg group.
The egg group Water 2 Pokémon are generally based on fish.
- Water 3 is connected to Bug / Flying / Water 1 and has 33 Pokémons in this egg group.
The egg group Water 3 has a mix of different Pokémon types, including fossil Pokémon, crabs and invertebrates.
- Ditto is connected to all egg groups except itself and the Undiscovered group and has 1 Pokémon in this egg group.
The egg group Ditto has the Pokémon Ditto in it.
- Undiscovered is connected to nobody and has 112 Pokémon in this egg group.
The egg group undiscovered can not breed with any Pokémon. The group mostly consist of Legendary and baby Pokémons.
Example: Let's say you have a Pokémon in the Fairy egg group with a move you want to breed onto a Pokémon from the Dragon egg group. There are no Pokémon in both groups so you'd need to find in intermediate group. Looking at the rows for both Fairy and Dragon below you'll see that the groups Field, Flying and Water 1 connect to both. So you'd need to breed the move onto a Pokémon like Pikachu (Fairy/Field groups) then onto a Pokémon like Arbok (Field/Dragon groups).