Because it deserves it’s own thread I’ll update it as I go along:
Juri: standing only possibly with the meatiest of meaty Knees, just grazing her own knee. Haven’t been able to combo into it other than that.
crouching: s.MP works, from jumping attacks (nj.HP, j.HK, j.HP) into s.MP need to be deepish otherwise won’t work.
Chun-Li: both standing and crouching only the meatiest Knees work.
Dhalsim: standing s.MP is possible but extremely tight, also meatiest Knee works.
crouching: nj.HP > s.MP xx Knee again possible but extremely tight and also meatiest Knee works.
Abel: standing: very meaty wake-up Knee works.
crouching: meaty Knee (doesn’t need to be too meaty), meaty wake-up Knee, “cross-up” Knee (have to input Ultra backwards but it works ), Gadouken FADC > s.MP xx Knee (very tight) works.
Viper: standing: meatiest Knee and very meaty wake-up Knee works.
crouching: meaty Knee, meaty wake-up Knee (pretty damn meaty but not overly)
Bison: standing: Gadouken FADC > s.MP xx Knee, deep nj.HP > s.MP xx Knee, meatiest Knee, meaty wake-up Knee works.
crouching: pretty much any naked Knee, s.MP xx Knee if it combos, nj.HP > s.MP xx Knee, meaty wake-up Knee works, “cross-up” Knee (Ultra motion backwards to work).
Sagat: standing: only meatiest meat lovers Knee and super tight link too.
crouching: only cross-up Knee, have to input motion backwards as you land on other side.
Cammy: standing: meat feast Knee and very meaty wake-up Knee.
crouching: any bare Knee, s.MP xx Knee, nj.HP > s.MP xx Knee, meaty wake-up Knee.
DeeJay: standing: only a huge HAM of a Knee.
crouching: bare Knee, s.MP xx Knee very tight link.
Cody: standing: super meat only.
crouching: any bare Knee, s.MP xx Knee not too tight.
Seems like you need to hit the Knee on the very last frames to be able to land the Ultra…