This is not a combo video to show off impractical combos! Nearly all of these combos are useful in some capacity in an actual match. They are all relatively easy to do, especially the corner scream ones. Obviously you don't always need to jump punch to start these off. They can be used as punishers. For instance, B3, F2 is a good punisher for blocked teleport attacks. You can also use 4, 4.
I find that 4, 4 is the easiest to combo off of without making mistakes (but it's also the weakest). For Sindel, you're not trying to utilize a bunch of combos in matches anyway. It's best to keep it as simple as possible without taking unnecessary risks. It's also best if you can position your enemy in convenient areas (that's why I showed combo 10 even though it's practically the same idea as combo 4 and 7 but with less hits.. which is also important). If you manage to get a random scream in, push them closer to the corner before starting your move.
Scream combos are a bit annoying so I don't recommend them unless you absolutely know you can get the timing down. The corner ones aren't a problem since the window from the F3 into scream is nearly impossible to mess up. Sadly you most likely won't get a combo off with Sindel in the corner often. And when you do it'll prolly be breaker'd.
Remember, it's better to get consistent damage off your opponent than trying to do something flashy. Sindel is already a weak character and using her meter during combos is not ideal since her enhanced ground fireball is one of her best wake up attacks. I only threw in one enhanced combo since it's stupidly easy to do and it does a nice amount of damage for very little effort.
Combo 1: 0:00
jp, 4 4, b12, dash, 4 4 ~ df1
Combo 2: 0:06
jp, b3 f2, dash, 1, b24 ~ df1 (the fireball combos but doesn't show in the %)
Combo 3: 0:13
jp, b3 f2, f3 ~ df3
Combo 4: 0:18
jp, b3 f2, dash, 31 ~ db2, jp, 21 ~df4
Combo 5: 0:28
jp, b3 f2, f3 ~ db2, 31 b2, d1 ~ df3 (you can also end this with X-Ray)
Combo 6: 0:38
44, b12, 1, 44 ~ df3
Combo 7: 0:44
jp, b3 f2, dash, 1 ~ db2, jp, f12 ~ df2
Combo 8: 0:54
jp, f3 ~ db2, 31 b2, 1, 44 ~ df3
Combo 9: 1:03
jp, b3 f2, b2 3 ~ EX df3
Combo 10: 1:09
(opponent in corner) jp, b3 f2, f3 ~ db2, jp over into corner, f3 ~ df2