None of the odd egg Pokemon are particularly good for playing the main story because they take a lot of experience to level up and catch up to their teammates. If you're absolutely sure you want to use an odd egg Pokemon, then the best will be Tyrogue. If its physical attack is better than its physical defense, then it will evolve into Hitmonlee, which has good typing and physical attack and passable special defense and speed. It learns high jump kick at level 26, which is pretty early. If you're okay with not using the odd egg, then these are the "better alternatives" to each odd egg Pokemon.
Pichu: Chinchou
Cleffa: Spearow
Igglybuff: Spearow
Tyrogue: Poliwag
Smoochum: Abra
Elekid: Chinchou
Magby: Growlithe
