Abra can be caught on the route south of Goldenrod City, whereas Machop can't be found until you reach Mt. Definitely a great alternative to Geodude.Ī trainer offers you their female Machop in exchange for Abra inside the Goldenrod City Department Store.
Onix is great for the first and second gyms and will prove useful in the fourth, seventh, and eighth after it evolves into the Steel-type Steelix. This trade offers you a strong Onix in exchange for the rather common Bellsprout, which can be found outside of Violet City in the grass. The first trade you are offered is made in a home in Violet City.
It's up to you whether you want to make the trades or not though so choose wisely. Some of the trades offer rare Pokemon for common Pokemon, and some offer rare Pokemon for rare Pokemon. Only one Pokemon in the game is only gotten via trading this time around, and you won't encounter it until Kanto. Trading with non-player characters makes a return in Crystal.