Traction is a measure of how far a character can slide on the ground, either by shielding an attack or by wavedashing. It is generally considered best for characters to have a moderately low traction, so they can wavedash an optimal distance.
Traction ranking
This is a ranking of each character's traction, from least to greatest.
1. Luigi
2. Ice Climbers (Except on ice, where their traction is best)
3. Mewtwo
4. Marth
5. Yoshi
6. Roy
7-9. Dr. Mario/Mario/Mr. Game & Watch (all equivalent)
10. Samus
11. Ness
12. Fox
13. Bowser
14. Falco
15. Young Link
16. Ganondorf
17. Donkey Kong
18-19. Pikachu/Sheik (equivalent)
20-21. Captain Falcon/Kirby (equivalent)
21. Pichu
23. Jigglypuff
24. Link
25-26. Peach/Zelda (equivalent)