The methods of motion from slowest to fastest are:

The jet pack has 60 units of fuel, each lasting 15 frames. Fuel consumption does not depend on if you are moving or not, thus the jet pack provides 900 frames (00:12.84s) of flight.

Normally when Dave is is in falling mode (not in jump) with horizontal momentum, releasing left or right makes motion continue. You can fall vertically by releasing left or right and hitting up.

Hit the direction you are going to first and then release the direction you are currently going at least one frame later. This makes Dave turn one frame faster. Note that with some directions Dave turns on press (especially up) and for some directions on the release (left or right).

Hit the jet pack or fire button and then release it on the next frame. This may fail on some lag frames or if you are releasing or pressing some other button at the time. This is the fastest way to fire the gun or activate/deactivate the jet pack.

In level 6, grab the jet pack and fly to the door without the treasure. You fly through the door. Then go left over the edge of the map. You are transported to glitched map. This is not useful, because you are frozen for about 15 minutes after entering the map and the map seems impossible to complete without cheating.

Begin the same way as in glitch warp but instead of going left, go right. You eventually stumble into secondary area normally accessed from level 8. If you collect the secondary area treasure and go through the door, you are transported to level 7. This isn't useful in fastest any% run since you can get the primary area treasure and exit faster than you can get the secondary area treasure and exit (and both exits go to the same level).

In levels 5, 8, 9 and 10 you can go over the left or right edge of the map. If you do so, you are transported into "secret level" (in fact, these levels are parts of other levels normally impossible to reach^[1]). You can't enter secret levels recursively (you stop at the map edge). If you complete the secret level, you return to level you entered it from (not the next level from there).

The levels that have warps are noted in the game ending text.

[1]: The secret level accessible from level 8 (part of level 6) is the exception, that one can be accessed through a glitch. For the rest, no way to access from target level itself without cheating is known.