Swift Swim according to type distribution:

Poison:

1. Qwilfish

Dragon:

1. Kingdra

Fighting:

1. Poliwrath

Ground:

1. Mega Swampert
2. Palpitoad
3. Seismitoad

Ice:

1. Beartic

Rock:

1. Omanyte
2. Omastar
3. Kabuto
4. Kabutops
5. Relicanth
6. Anorith
7. Armaldo
8. Tirtouga
9. Carracosta
10. Drednaw

Bug:

1. Anorith
2. Armaldo

Grass:

1. Lotad
2. Lombre
3. Ludicolo

Flying:

1. Mantine
2. Mantyke

Bug:

1. Surskit
2. Anorith
3. Armaldo

Water.

1. Horsea
2. Goldeen
3. Seaking
4. Magikarp
5. Omanyte
6. Omastar
7. Kabuto
8. Kabutops
9. Qwilfish
10. Mantine
11. Kingdra
12. Mega Swampert
13. Lotad
14. Lombre
15. Ludicolo
16. Surskit
17. Feebas
18. Huntail
19. Gorebyss
20. Relicanth
21. Luvdisc
22. Buizel
23. Floatzel
24. Finneon
25. Lumineon
26. Mantyke
27. Tympole
28. Palpitoad
29. Seismitoad  
30. Psyduck
31. Golduck
32. Poliwag 
33. Poliwhirl
34. Poliwrath
35. Tirtouga
36. Carracosta
37. Chewtle
38. Drednaw
39. Arrokuda
40. Barraskewda

Edit (01.01.2020): Added Sword and Shield additions.