Some feedback for users that arent on the discord or I havent responded to yet:
DrifblooomCF This is a very interesting concept, but some things I'd heavily consider with this idea is that there is a very large focus on the wings and bird aspects, which push the design out of the poison/dark typing. Normally, I would usually feel okay if a mon looks multiple types as long as it can encapsulate the types we need, but it's very hard to not see this as part flying, which evidently knocks one of the other two required types off the table. Additionally, the heavy use of pink doesn't feel like it's enough to invoke a poison typing, despite the plague doctor motif that I think is there. I would definitely suggest reevaluating the design elements you want to focus on in this design so that it pushes the typing in a more understandable way.
JAGFL I love designs that use primarily white, and I think the colors you chose here show off the typing in a very different and fun way. I think the only thing that might need to be looked into is that pokemon that were based off of mushrooms are grass types, with the two poison-type mushrooms being part grass as well. From a first glance, it's a bit hard to see this design being dark type, and if anything, the colors paired with the mushroom concept seems to push a fairy and grass typing instead, similar to that of shiinotic and morelull. If mushrooms are your concept that you want to keep, I think emphasizing the darker elements of the design may push the dark typing out more.
JJslem This is a fun and goofy design, but my first impression of it is that im sort of confused as to what exactly it is. It's important to remember that the people voting on your design will most likely not take the time to look through whatever description or explanation you have of it, so it's vital to make your design understandable at a glance. Whatever this is based off of, it would be nice to see you flesh this out a lot more and create more understandable elements to draw the viewers' eyes around. Right now I see that there are tentacles, so maybe making it resemble more of an octopus or squid will help in that aspect.
Magikarpet ride A very simple but nice design that is easily readable. I think the only thing you should work on is making a pose that looks more interesting, and maybe making the main body larger as to create a better point of interest for the viewers. Playing around with some sort of pattern on the main body instead of random dots will also create a much stronger identity for the design, since as of now it doesn't seem to really make me feel strongly for it.
Magmajudis Cool snake, only thing I think this design needs to do is use a slightly brighter set of colors so the colors can be better read, and to reduce the amount of colors on the belly. Less is more in this case, so creating a pattern of 3 or so colors really helps the design look more organic.
SunMYSER I am immediately attached to anything with a mohawk/afro. This design is really cool, but it feels very detailed in the folds on its back and the small details that are everywhere on its body. Removing many of the folds and limiting the number of spikes that run down its head to its back legs would create a better focal to look at. It's a situation where having less spikes creates more identity to each individual spike, while having too many like you do now makes it feel too cluttery and makes eyes pass over it.
The Metric System A very fun design, and probably the most different takes of the typing and ability ive seen yet. I can't really comment much on this without destroying the idea you have going for it, so the only thing id really like to say is that i think the hat on the green one could look more unique, so that it pushes the design into becoming more interesting. It doesn't have to be a grandiose change, but something that says a little more than just "a hat".
The Unseen Potato I actually had to read the description for this one because I didn't actually understand what this was. Similar to my advice for JJslem, I think this design should have more understandable design elements to it so the viewer can tell at a glance what it's about. Not to say it's a bad design, but it's good to keep in mind that your voters will most likely vote based on their first impression of the look, and if you have to explain what it is to them, they'll most likely miss that explanation. Another thing about the design is that there don't seem to be a lot of points of interest for the viewer to look at, besides the pipe hat, which ends up making the design feel a bit too simple and uninspired. I believe if you added strange shapes to it, similar to that of what you did for the face, it would then at least push that aspect better. You mentioned that it was some form of escaped blob, so it would be kind of interesting if you pushed that into the design as well.
flying moose I saw you talk about this concept in the discord I think, and it's a very fun concept to work with. The shapes on the back are what I think makes this design look very fun, but the main body itself feels a bit too simple compared to them. It would be interesting to see the main body have more of a form to it.
sgtxam This is concept I had a hard time understanding, so I'm just going to give feedback on the design itself. I think the head is a bit far too large and oddly angular compared to the rest of the body, and what I believe is smoke on the head is hard to read in its current form. Additionally, the head being so large creates a large focal point at its head, but it also being black and monotone makes it push that focal away from it. This kind of creates a bit of a jarring look since it looks like it's supposed to be the "cool" part of the design, but it ends up going to the body instead. For what I believe is the smoke, I think making the wiggly lines more shaped instead of conforming to the contours of the head will make the head far more interesting to look at. The camo on the body is a very nice touch though, and is one of the few times i appreciate designs with many colors on it.
Advice for everyone here in general: Please feel free to ask for feedback on the Discord server! Everyone can only say so much in a forum post, so seeing a live update of feedback from a lot more people tends to help much better, for you and your feedbackers :)