Depending on the terrain, there are two possible outcomes when going from an elevated area to a lower one:
When the 2nd case happens, and with the help of a source of damage, it is possible to use the fact that Link is gaining height during his jump to get on top of things, like ledges.
The timing to get the trick is very precise. It works with both Bombs and Nice Bombs, although the Nice ones make it a bit easier to pull off.
Due to the difficulty of performing Bomb Boosts by jumping off a ledge, and the fact that other damamge boosting methods are easier to pull off, it generally isn't used in speedruns. Nonetheless, here are the current potential uses:
This is perhaps the most consistent form of Damage Boosting currently known. The draw back is of course that Nice Bombs are required, which are often too far out of the way to be worthwhile in speed runs.
By placing a Fire Pillar into a corner and jumping off a ledge just above that corner, you can take damage and get boosted while in the air. This is possible with the Nice Fire Rod and, depending on the location, can be possible with the regular Fire Rod, although that version will require the use of the QE-Canceling technique in order to gain control of Link earlier and jump off the ledge in time.
You have to be standing a small distance away from the ledge you want to jump from. You'll want to be far enough away so that your Fire Rod shot will go on the ground for a tiny bit, then fly off of the ledge. So, QE-Cancel a Fire Rod shot, then quickly run to side of the pillar, jump off the ledge and get hit by the pillar that is floating off of the ledge.
Requires the Nice Fire Rod. You shoot a fire pillar up against a wall on the ledge you want to jump from. Get hurt from the fire pillar then stand in it from whatever point you want to jump from. Then as your invincibility is wearing off, jump off the ledge so you get hit from the fire pillar.