Based on looks alone, because I don't like the Pokemon games. I tried one once, and it's just too much level grinding for me. Of what little I played of the first Pokemon game, I seemed to like Spearow.
1. Mightyena (#262)
2. Arcanine (#59)
3. Vulpix (#37)
4. Pidgey (#16)
5. Miltank (#241)
6. Ho-oh (#250)
7. Cubone (#104)
8. Buizel (#418)
9. Murkrow (#198)
10. Bidoof (#399)
11. Nidorina (#30)
12. Leafeon (#470)
13. Eevee (#133)
14. Xatu (#178)
15. Numel (#322)
So that's 6 from first generation, 4 from second generation, 2 from third generation, and 3 from fourth generation.
There's Pokedexes all over the place, but
here's the one I was just using. Only goes up to Pokemon #490.