Been getting all the % that peach's moves induce tumble vs. the cast. The % is based on character weight. So the same move will cause Pichu to tumble at earlier % than Kirby, who in turn tumbles before Marth, etc.
Here's the order from lowest to highest % tumble inducing moves: [hitbox description, CC or not] (Pichu - Bowser, the chart will have all weight classes when its done though. ? means I didn't test bowser/Pichu yet, since I sorta do things in a scatterbrained way)
1. Golf Club [17 damage], d/b/u throw, up-smash [19 damage], Tennis racket [12 damage],
Fair, Down Tilt [vs. grounded opponents], and Dash Attack [12 damage]: ALL induce tumble at 0% against the entire cast. IIRC stitchface also induces tumble at 0 but I haven't confirmed yet.
2. Up-smash [15 damage] (?-6%)
3. Frying Pan [17 damage] (2-?%)
4. Up-Tilt [12 damage] (9-18%)
5. F-Tilt [13 damage] (13-24%)
6. Strong Nair [14 damage] (16-27%)
7. Golf Club [13 damage] (?-30%)
8. F-tilt [11 damage] (19-?%)
9. Up-air [14 damage] (20-34%)
10. Down-Tilt [12 damage, crouch canceled] (22-35%)
11. F-tilt [10 damage] (23-?%)
12. Down-Tilt [12 damage, 70° trajectory] (26-41%)
13. Up-Smash [8 damage] (28-?%)
14. Up-Air [12 damage] (27-47%)
15. Back-Air [14 damage] (29-?%)
16. Up-Air [11 damage] (31-?%)
17. Back-Air [10 damage] (46-?)
18. Nair [10 damage] (48-?%)
19. Nair [9 damage] (54-?%)
20. Jabx2 [5 damage total] (84-119%)
21. Neutral Tossed Normal Turnip [6 damage] (96-high%)
*Peach's Forward throw (when fresh) always induces tumble at 27% regardless of character thrown.
*1st jab never induces tumble. It can force a getup when used to Jab reset vs. MewTwo, Marth, Roy, Young Link, ICs, Peach, Zelda/Sheik, Ness, Mario and his clones, Link, CF, Yoshi, Ganon, Samus, DK and Bowser. Pichu, GW, Jiggs, Kirby, Fox, Pikachu and Falco are too light, and can roll, getup attack, etc.