Aht Urghan Immortal needs to specify when its triggered ability happens. Usually this is in form of an upkeep trigger like
"At the beginning of your upkeep, roll a d6."
Arciela should just say Flash and Haste, the latter being a red-centric keyword.
I know you're using MTGSetEditor (can tell from the square set symbol) but there is a later addon for nickname tags below the title. Boyahda Tree is a "Wastes", and should be templated as such.
Likewise with all the other lands.
Any reminder text should be italicized and in parenthesis, in the case of Bakgodek:
(This creature cannot be blocked except by two or more creatures.)
Likewise with flavor text being italicized, in the case of Genbu.
Lilisette's ability would read as if she is granting lifelink to each creature you control permanently. That sort of thing is Arena-Exclusive but wouldn't fly in paper. Just make it another upkeep trigger so it would at least happen on every turn or every one of your turns.
Maat should read "As long as an equipment named Glanzfaust is attached to Maat, it gets +4/+4."
Edit: Look if you want to use AI art, fine. At least put it in the bottom where the illustration name would be. Some of these would be better off being screenshots from the ingame client/promotional art with proper credit.
Mielikki should read "When Mielikki enters the battlefield, you may cast up to one sorcery card from your graveyard this turn." or "Target sorcery card in your graveyard gains Flashback until end of turn".
Ochain should say "Counter that spell", not "negate that spell entirely". As well as "Equipped creature gets +0/+4".
Odin should read: "When Odin enters, destroy target creature, then exile all Auras and Equipments on another target creature."
PW should read "When ~ enters, create eight 1/1 red(?) Dvergar creature tokens. All Dvergar gets +1/+1 for each other Dvergar on the battlefield". See Coat of Arms from Xth Edition for reference.
Prishe should read "Whenever Prishe is blocked by a creature, it deals 2 damage to that creature." No need for 'additional' since this is done before the combat step.
Red Mage should just say Haste.
Shantatto's +2/+0 counters almost never exist anywhere else except for two cards in a set in 1994. Either stick with +1/+1 counters or have her read something like:
"~ gets +1/+0 for each instant and sorcery card in all graveyards"
Sov. Behemoth is actually formatted correctly. Well done. You don't need to capitalize "Red Creatures", though.
Twashtar should read "Equipped creature gets +1/+0. If ~ is attached to a creature named Lilisette, when that creature attacks, roll a d6." "4~6 - Until end of turn, Lilisette gains lifelink and 'Triple all damage this creature would deal'", See the new Wolverine for formatting.
Just give Valaineral a +1/+1 counter. Don't reinvent the wheel.
Vidmapire is "As long as" not "So long as"
V. Cluster should read "When ~ dies, it deals 5 damage to each player."
===============================================================
Now that I'm done being your proofreader: I know you put in the work in these, but you gotta make sure it looks the part if you want to make it feel like a Magic card. That includes word formatting/templating. As well as the usage of the correct borders (AV should not have a multi-color border for a mono-red creature.) And that's not even going over how impossibly color-pie breaking most of these are.
One other thing: the most popular format right now is Commander. Anything with "Legendary Creature - whatever" is going to catch someones eye and potentially spark a creative deck process. None of these named figures like Arciela, Lili, Valai or Shantotto, except for Absolute Virtue for
some reason, have "Legendary Creature" in them.
And, I wouldn't really care about this so much but you're selling this. For previously 50 USD now half that price. For cards that are underpowered compared to what WotC is printing today. I know it's a novelty item and I get that, but AI Generated Art isn't appealing. I look at Prishe and just see some chinese kusuge character, Valainarel looks like something out of a rejected Tencent character profile. Shantotto actually looks more Lalafell than Tarutaru and thats saying something.
The only reason why I'm saying all this is because you did put in *some* care into this project and I honestly think doing something like this is awesome. It just needs work. A lot of work. Ditch the AI ***, study existing cards and their templating, and know that MTGSetEditor isnt the only resource out there to make good looking cards.
Also, I know I'm taking a lot of people's time, but Shantotto's flavor text literally doesn't rhyme.