Maybe those combos are already known, but I haven't seen them on this topic and never in videos nor battles online, so I'll share what I "discovered". I've been training mostly with throws these last few days and came up with fragile but highly damaging combos. In fact, there is even a way to infinite grab your opponent to death (except that your opponent will most probably break free quickly enough) when you succeed in landing an air throw. Here's what I like to do:
5C CH -> 6C -> 236CC -> 2d~6 -> j.C -> 8d~6 -> j.C -> 8d~6 -> 236BB -> B+C -> 214D -> 44 -> B+C
Basically, when you fall from your first air grab, you have to bufferize the 214D which will make you jump immediatly. On most of the cast, you will go past them, hence the 44. Once you're really close, you can grab again. Oh, and it's an air grab too. Therefore, starting from this point, you can rinse and repeat 214D -> 44 -> B+C to grab your opponent until he escapes. The odds of killing him with this combo are pretty low, but you can land a few grabs until he realizes what is happening to him. For example, the combo that I wrote above inflicts more than 6k damage and is quite easily done. You can add much more if your opponent doesn't escape.
You can also grab after the 2d~6 in any drive loop, and send another drive loop once your opponent falls back on the ground. There are a lot of possibilities.
(FYI, I've tested the 214D->44->B+C on all the characters, and it works well on everyone except Tao, Arakune, Rachel and Carl. For Nu, you have to replace 44 by 66 and it should work well.)
My bad for the probably bad english, It's been some time since I last wrote a lot in Englsish. Hope my little contribution will be usefull to someone (and I still hope something like that wasn't already written in this thread, if this is the case then accept my deepest apologies... :p ).