everyone should play around with this. definitely think it makes shinnok a lot better since he has a hard time being safe
The most useful ones I've found so far:
anything xx DB2~(B or F) = DB2 on hit, nothing on block
anything xx BF3~(B or F) = BF3 on hit, nothing on block
(NECROMANCER) anything xx DB2~F = DB2 on hit, BF2 on block (can't input the DB2 too early or the B2 doesn't stay in the buffer long enough for BF2)
(IMPOSTOR) anything xx DB1~F = DB1 on hit, BF1 on block (can't input the DB1 too early or the B1 doesn't stay in the buffer long enough for BF1)
(IMPOSTOR) anything xx DB1+block~F = DB1 on hit, EX BF1 on block (can't input the DB1 too early or the B1 doesn't stay in the buffer long enough for BF1)
~B and ~F have to be input after the hit-cancel window, but before the block-cancel window. I believe they work with any cancellable normal, but I'm not sure. B3 works for sure, which is the most useful one.
EDIT: Corrected last OS. Block has to be input at same time as 1, not after 1.
EDIT 2: For the first two OSs, if the button for the special is the next hit in the string, you get the next hit on block. If you want to do the next hit in the string on block and the next attack is a different button than the special, you can input the attack button anytime after inputting the special and it will come out on block if you time the ~B/F correctly. The first OS also does not work with DB2~F on Necromancer unless the DB2 is input far in advance (so B2 leaves the buffer); otherwise you get BF2 on block. Also, obviously the last 3 OSs don't work on alternate controls as is; you have to input the full half-circle instead of just hitting ~F.