Liepard - Bonbon Blvd. (stage 87) - Base power : 60
Gengar - Castle Noapte (stage 125) - Base power : 70
Scizor - Jungle Verde (stage 143) - Base power : 70
Heracross - Jungle Verde (stage 148) - Base power : 70
As you can see, you find these Pokemon fairly far in the game. Every Pokemon increases approximately 2-3 attack power each level. So, there is a high chance that liepard will have an attack power of 80 at level 10, and gengar, scizor, and heracross would have an attack power of 90.
Hope I helped! :)