note: when I simply say "reduced" or "boosted", it refers to a difference of less than 10 points. "significantly booster/reduced" means in the ballpark of 20 points, and "greatly boosted/reduced" means it's like 30 or more.
- Caterpie - Learns Bug Bite early on, delayed evolution into Metapod until level 11.
- Metapod - Sp. Def increased to be on par with its Def. evolves into Butterfree at 15.
- Butterfree - Butterfree HP, Atk, Def, Sp. Def all increased, stat total now 420.
- Pidgey line - swapped names so that it goes Pidgey>Pidgeot>Pidgeotto, HP and speed boosted significantly.
- Sentret line - atk and speed boosted, evolves to Furret at level 21, where it has a speed of 130.
Poliwhirl, Shiftry, Raichu, and more after the jump:
- Poliwag line - slight stat boosts, evolves to Poliwhirl at level 20 and to Poliwrath at level 40, where it will learn Submission, Waterfall, and Superpower.
- Seedot - boosted HP and Def greatly, learns Nature Power before evolving to Nuzleaf at level 12
- Nuzleaf - reduced Atk and Sp. Def and boosted Sp. Atk and Def. Evolves to Shiftry at level 35.
- Shiftry - reduced Atk and boosted Sp. Atk. learns Leaf Blade, Crunch, Silver Wind, and new move Telekinesis.
NEW MOVE - Telekinesis - Psychic, 80 physical power, 100 accuracy, small change of causing Flinch.
- Treecko line - significantly boosted Atk and significantly reduced Sp. Atk, Leaf Blade is learned much earlier, Sceptile learns Frenzy Plant at level 55.
- Mareep line - boosted HP and Def, learns Volt Tackle at level 56.
- Chikorita line - reduced Def and Sp. Def, boosted HP, Atk, and Sp. Atk. gender biased to be 87% female.
- Spinarak line - boosted Atk, Def, and Sp. Def, significantly boosted HP
- Pichu - evolves to Pikachu at level 10.
- Pikachu - boosted Atk to be stronger than Sp. Atk, Spark is its most viable move, evolves to Raichu at level 30.
- Raichu - boosted HP, Def, and Speed, significantly boosted Sp. Atk, learns Thunderbolt, Thunder, and Volt Tackle in this form.