For Pokémon that show no sexual dimorphism, I'll make it up myself. I'm calling it "cleaning up".
- Bulbasaur: Female has hearts on forehead.
- Ivysaur: Males' buds are longer.
- Venusaur: Already one. No need to be cleaned up.
- Charmander: Females are larger and plumper.
- Charmeleon: Same as above.
- Charizard: Females' wings are longer.
- Squirtle: Males' tails have more spirals.
- Wartortle: Males' ear fins are longer.
- Blastoise: Males have longer claws.