Well, your user title pretty much says it all; these are pretty intermediate. I don't find them particularly poor or good, but considering you supposedly have hundreds of sprites you ought to get better and better so either you've been doing something wrong for a very long time or you have other issues.
Anyway, the biggest problem on most of them is the outline. The Deoxys is a prime example, its outline is downright terrible. On some others (Mewtwo/Elektabuzz & Rayquaza mostly) the outline is too light in some places and too dark in others. It's a delicate balance you haven't found yet. Also it bugs me that while copy/paste'ing is acceptable to some degree (however at 'intermediate' level you should stop doing that unless it fits perfectly), you need to edit the shading when you do so, especially if you rotate/flip parts, because the lightsource will be all messed up. Best example of this is once again the dual Rayquaza.
Another problem your sprites have is that they're...overcrowded. It's a problem I see a lot of times with beginning spriters and the cure for that is - listen up, breaking news here - to KEEP. IT. SIMPLE. Hydreigon/Arbok is a cool idea but it does NOT need 5 heads, especially if you don't know where to place them, don't shade them correctly, etc..The same thing goes (perhaps even more so) for that Mewtwo/Vulcarona abomination, I can't even begin to figure out what that's supposed to look like.
However, and I hope you haven't stopped reading already, it isn't all bad news. You have some potential; the weather Mewtwo looks pretty cool (once you ignore the obvious shading problems and the fact that it's just flipped), and actually - to be 100% honest - I could see a lot of these ideas work if you fix the numerous issues they have.
For your convenience, here's a little tl;dr version:
1. KEEP IT SIMPLE
2. Practice on your outline work
3. If you're gonna copy/paste, alter the shading accordingly.
I'll need to see more to make a more definite judgment of your capabilities, but I ain't checking your hundreds of sprites on Youtube or anything like that, so either show us the best you got (if you haven't already, idk) or try to fix these the way I suggested to and then I'll have a better idea of what you can do and if and how we can make it better
.
Welcome to our spriting community.