Fade In
Suppose the t-value for the current Dialogue's start frame is 9.042, the t-value of the current Dialogue for the current frame is 2094.458, and the 1st, 3rd, 4th alphas of its style are 0x00, 0x00, 0x80 respectively. Then this command will generate
and send it to the clipboard. Which is basically a high-quality version of {\fad(2094,0)}. For the optimal results, you may need to further tweak some parameters manually, for example the accel parameters.
Fade Out
The opposite of Fade In.

Split [J]
Join Next [RCtrl]+[J]
Join Prev [LCtrl]+[J]

For example, suppose the current Dialogue is:
Dialogue: 0,0:00:01.75,0:00:08.00,SomeStyle,,0000,0000,0000,,Text
and the current time is 0:00:06.33. Then Split will generate the following 2 Dialogues and send them to the clipboard:
Dialogue: 0,0:00:01.75,0:00:06.33,SomeStyle,,0000,0000,0000,,Text
Dialogue: 0,0:00:06.33,0:00:08.00,SomeStyle,,0000,0000,0000,,

Join Next will join the current Dialogue and the next (according to line numbers) Dialogue and make one Dialogue. Join Prev will join the previous Dialogue and the current Dialogue.