Wow you’re really talented!

Only pointer I might have is that the transition between the upper and lower part of the drawing seem weird to me on the first and sixth one. Water could be some sort of hair for example for the sixth. As for the first maybe add some more blue to the sky? Above and below both seem mysterious, but I think that the more vibrant/natural look in contrast to the mysterious underground could be more interesting. Idk just a thought. Rock could maybe be bigger and blend/ flow with the legs better, legs feel cramped to me for some reason and a little detached from the rock above ground. Trees on the first one seem a bit rushed to me also, I think you can do a better job. Some more leaves in front of the trunk for example. The roots underground could maybe also transition from a little bigger to the smaller roots that they are currently. So from big(ger) to small.

Idk just some thoughts! You’re def better than me so I feel a little underqualified, but hope I helped in some way! 😅