Found a few new skips recently, figured I would gather them here and explain them along with the one I found on 4-2 a while back;
4-2 (Rocky Peaks 2);
Idea behind the skip is to touch the first cloud platform for a single frame then fall off, this gives rayman the properties of the cloud (rising if its rising, falling if its falling) and puts rayman in a weird state. Then you want to float to the ledge shown in the video (While the platform is rising, if you unload the platform while it's falling you'll sink instead) and you'll automatically rise up. Make sure not to jump off of flat ground as this loses the rising property, you have to float from the platform/ledges (jumping from a ledge is fine, only jumping off of flat ground loses the property).
There are a few setups to get this, my personal preference is to hang off of the first ledge and time a Right into immediate A button tap.
SkeletKasket has a jump from spawning in setup that also works (I'm not sure if its easier or harder, I know I suck at it though.)
4-3 (Rocky Peaks 3);
You want to grab the initial edge in all of the spikes in the video below (at the bottom of the area just below the first moving spiked rock), and then look left. Once you take damage again this should knock you down to holding a lower platform, simply look right and then drop down, you can fall the rest of the way without inputting anything safely and then pick up the heart right at the bottom.
6-1 (Fiery Depths 1);
When you get to the first bat hanging loop, ride it to the top, jump into the spikes and then position rayman into the small gap shown in the video below. You then want to die, and you'll respawn at the checkpoint on the other side of this wall. Ideally you want to enter this level with 2 health, one to take the initial hit then die on the second, if you have more though you can take damage on the first two flamethrowers and then the swinging ball in this level on the way to this point.
6-3 (Fiery Depths 3);
After the first swinging ball and the drop, simply helicopter into the gap in the wall shown in the video. This trick now means you need to enter this stage with at least 3 health, ideally 4+. This is the biggest of the new skips found, and thankfully the easiest.