@Bumibu
First, how did you make the customs?
Second, let's look... I have't looked at other comments, so sorry if there's repeats.
Gub: Great effect. Perfect colors. Surveil doesn't need to be capitalized. If it proves slightly too strong, slap the effect onto a body so it's a bit more vulnerable.
Rgw: There's 0 white creatures with Undying. This should be any mix of colors other than what it is.
1Rgb: Is this supposed to monarch them and you try to immediately steal it? Needs more stats or something and doesn't feel very intuitive. As far as the colors go, I'm not sure who would give away monarch. Colors received monarch fairly evenly, so RB being reckless is about right. Feels Wrb to me?
1wbU: Change the name, fuck that release. Otherwise, feels right.
1ururW: Seems good. Could add haste or a toughness if it needs it.
Grw: Looks right to me.
1Rwu: Seems good if Sprite Dragon is a good fit.
1Wrb: Perfect mix of Wr double strike and Wb hate.
3Gwu: Can't help but feel this one is a little weaker. 5 is a lot of mana. That said, it's a lot stronger than Tatyova, so maybe I'm wrong. I don't know how I'd change it, either.
1gwB: Make this cost 2 and make Veil of Mold exile noncreature for 3 imo.
1Gur: This one's weird. There's nothing Gu or Gr about it. Maybe landfall for a ++ counter instead of the rummage?
1bwG: Fuck hitting lands for 3.
3Brg: Artifact doesn't need caps. Maybe he just makes a zombie, considering he's base black?
1wbR: This is weird to hit a historic permanent, wording-wise, but it's kind of just a Vandal. Seems ok, but unexciting. I'd want my R based Mardu card to SMASH.
rbrbG: Sweet.
Bur: No. No. No Skullclamp 2. Pass.
bgW: There's no green cards that care about historic. This doesn't make sense. Could be Esper in any ordering of mana, but not Abzan. Also, the wording is outdated.
Ubr: Some capitalization and wording issues, but this is awesome.
2?wUU: I can't see it well, but if that's a gw symbol, this is great.
3uwuwBB: Crazy mix of effects and very high mana cost. I can't tell if it's OP or slow or what. That makes it interesting, for sure.
Wgu: WotC wouldn't print this, but it seems strong and fine if there's only a single copy.
XUUbg: This is a really fun mix of effects!
1Urw: Having trouble assessing the power level, but it's intriguing, for sure. I'd leave it as is.
Bgu: Seems more like it should br Ubg as a mix of Strix and... that ice snake. Otherwise, we already know this card is strong and fine.
2ubR: Neat way to screw with a wheel. I like that the fateseal and scry are mild, as wheels are very strong.
1guR: Clean. I wouldn't be too mad if it were an instant, but sorcery is fine as well.
1Ugr: I personally hate tempo ETBs, but this is a cool one if you don't.
Wub: Is this just anti ramp? And makes fetches slow? I dunno. The trigger might be underwhelming, but it's on a good body, so that may cancel out.
1Brwrw: Feels a little RNG to me? Could feel really bad. I like the idea, but I'd hate to play with or against it. I dunno what else to suggest. It's possibly fine.
2brW: This heals the opponent if you try to remove their guy, ya? I'm sure someone pointed this out by now.
If you post these again, I'd love to have them color grouped like wuB wbU and Wub in a row.
Hope that was helpful. I only critiqued because I don't know what you're looking to add and it's way harder to design a card than critique one. Overall, I liked them. Even if I critiqued almost all of them.