Not super big rate only because I can't choose a couple to talk about. :P
So your first like 4 Pokemon ones are really good, however in the Foretress and Garchomp ones, I'd actually consider having the flow going the other direction for both of them. The Garchomp tag still looks great as it is, but it feels a little bit off, and the Foretress one feels quite unbalanced and off to be honest. But yeah, the effects and colours and everything are great! The Scizor one is, in my opinion, the best out of those couple, but yeah.
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This one could have been so very amazing if the colours were a little more interesting. The effects, depth and just general composition are stunning, and the only real thing I can see that let's it down is the colour palette, and not because it is necessarily bad, it is just such a common and overused colour scheme and it feels a bit generic because of it. Also perhaps it is a little over contrasted, but not too bad.
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This one is probably my favourite of the lot just because of the amazing colour scheme you've got happening and the whole tag is really sharp and crisp without looking low quality from over sharpening. That's actually a fairly tough stock to work with as well because it is quite symmetrical and doesn't give you much help in terms of flow, but your approach actually works really well and keeps it interesting.
There isn't really much I can tell you to work on, simply because you don't have any overarching issues or things that are consistent. If you have off colours in one, you have amazing in another and etcetera. I guess maybe that is something to work on, being more consistent. I'm assuming they are from newest to oldest, and your improvement is pretty impressive, however even the newer ones still have some little minor things. That Oddish one for example, really not an amazing piece in a few aspects, however your others more than make up for it. I don't know how long you spend on each piece, but l would recommend try spending a little more time just fiddling and playing around with your effects and colours and everything before you confirm it and move on. Try as many possibilities until you find something you either love, or just seems to work better than anything else.
Hopefully that wasn't too harsh towards the end, but yeah, you are a very good artist, very good at that typical sort of forum aesthetic. Maybe try moving on to more real life stocks however as well, just because that's the next step and you have nearly all cartoon / anime. But yeah, keep up the amazing work, and just try spend a little more time with your pieces!