Quick background - I've been playing Mythgard since September 2018, currently a Mythril player, and have directly contributed to various card changes and balance suggestions throughout alpha, some of these from memory included the following:

Shopworn Bull -> shuffles the deck

Shadow Trapeze -> Removed the 1/0 effect

Hekates Wheel -> Added a "while occupied" condition

Misanthropia -> Blight 3 instead of destroy all minions

Allfather's Horn -> Removed the draw a card effect

Dashing Ringmaster -> No longer a 3R 2/2 lurker with give rush to all your minions

Crimson Pact -> Destroy instead of banish

Many players have been submitting their list of balance suggestions based on extensive playtesting in open beta patch 0.16, and I wanted to put forward my two cents as well. I've had a lot of discussions with other players in Mythril/Champion over the past couple of weeks so many of these suggestions also incorporate their feedback as well. I wanted to post this on Reddit as well as Discord to expand the discussion to more of the community. I'll organize the following suggestions by color and give a quick breakdown of the key issue and a suggested fix/tweak. All feedback is welcome!

Paths:

The pursuit on Turn of Seasons does not compensate for being on the draw in a Turn of Seasons mirror. The player who goes first will typically have 5 mana to punish the first Winter (opening up options like Magnus and Magmataur), compared to the player on the draw who will typically have 4 mana to punish the first winter. A suggested fix would be changing the pursuit to provide 1 temporary mana on second spring.

Red:

"Rush" keyword in general is still undercosted for how beneficial the effect is relative to other keywords. Rhino historically used haste minions in MTG as a reference point; however, Rush is more powerful in Mythgard due to the lane system (whereas in MTG, any creature can be declared as a blocker). Over the course of alpha, Ringmaster has been nerfed 3-4 times due to the recognized power level of providing the Rush keyword; however, most rush units with an innate "Rush" keyword have yet to be adjusted accordingly. Generally speaking, I think all rush units can have their mana cost increased by 1 and/or their gem cost increased by 1 and would still see play.

Orpheum of Horrors is currently undercosted for its global damage effect in addition to its 1/0 strength buff, and I could see this being increased to a 3 cost enchantment that would still see play.

Blue:

Keeping in line with the previous Rush discussion, Freki Sidecar is slightly undercosted for the rush effect it provides, and would still see play at 4BB.

Rune of Denial is one of two reliable enchantment removal options in the game at a high cost of 4BB and is a reactionary spell (you cannot pre-emptively stop an enchantment and prevent the benefit). Therefore, it is already low tempo and suffers from the high cost. I believe this card could see more play if it was changed to either be more splashable (4B) or lower cost (3BB).

Blackened Jotun has one of the best statlines at 5B cost only (highly splashable) with 6/6 (highest stats) and Overrun (second best keyword). I think a minor nerf is necessary to one of these dimensions (cost, stats, or keyword) - so either 5BB (to bring it in-line with Volkov Heavy cost), 5/5 statline (but keeping it highly splashable), or change Overrun to Piercing or Blast 2.

Green:

Wake the Bones currently allows for really cheap recursion of important rare/mythic creatures with strong awaken effects with no drawback. In fact, its current cost at 1 mana means even if that creature was destroyed the previous turn, you can keep tempo by burning 1 card next turn, play Wake the Bones, and replay the creature for its awaken effect. This has been heavily discussed by many players piloting the current G/O control decks, and the various suggestions are the following: Creature returns with ephemeral from boneyard, change cost to 2GG, or change cost to 3G.

Rewind Hex currently is a 1 cost spell that can turn tempo immediately if it hits minion enchantment due to the fact that the enchantment goes back on top of deck. This is simply too much value for a 1 cost spell. Also a heavily discussed card, various suggestions include the following: Return creature enchantment to owner's hand, shuffle enchantment back into owner's deck and that player draws a card; if occupied, return the minion to owner's hand; or change cost to 3G.

Kolobok currently dictates tempo too much by being played T1 on the play in general; and in a mirror, T2 on the draw kolobok is a very bad play if T1 on the play also runs impel, warping the early game. One suggested fix to this issue would be to have Kolobok start with 0 energy if on the play; however, add the pursuit mechanic to Kolobok, so if on the draw, it starts with 1 energy.

Traitorous Murmur is a staple in most green decks and can swing tempo and occasionally win games by itself. It's also is one of the strongest targets for Bald Mountain / Recursionist. Suggested changes include the following: Banish after use, or change Murmur's Casting Cost to X 1 or X 2, where X = the mana cost of the target creature.

Orange:

Xerxian Recruiter is slightly overstatted at 2/3 with a high chance of drawing a card, and should be adjusted to 2/2 statline to bring in line with Firesong Prodigy.

Resupply Caravan is arguably better than Freki Sidecar at the moment and is undercosted for the effect it provides. Suggestions include: changing the cost to 4OO, 4OOO, or restricting the awaken effect when occupying a Desert Enchantment.

Serendipity Ifreet is overstatted at 4/4 for 3O cost. Divination 3 is a great effect, and its highly splashable at 3O. Suggested changes include: reverting the statline to 4/3, or changing the cost to 3OO.

Seal of Exile hearkens back to the old alpha Crimson Pact (which banished a creature), but layers on additional benefits for the -1 gem/mana sacrifice. I think it's interesting to keep the potential added value of exiling all copies from lanes, hand, and boneyard; however, also deleting copies from deck is very limiting for deck creation and building around certain creatures (for example, Alkonost, Jotun Shatterfist, Cadejos), as well as decks building around creature consistency (for example, running 4x of a common creature like Necromantic, Volkov Heavy, Shinobi, Meso Libre).I suggest removing the exile copies from deck effect, but otherwise keeping the other existing effects.

Yellow:

White Cadejo and Black Cadejo used to both be 3/5 creatures; however, after nerfs, White Cadejo is now 4/3 whereas Black Cadejo is now 3/4. In terms of their respective effects, I think these statlines should be swapped, so White Cadejo is 3/4 and Black Cadejo is 4/3.

Purple:

Sword Saint is similar to Xerxian Recruiter and Firesong Prodigy, and should be a 2/2 statline given its Awaken effect.

Racer in Shadow , similar to other rush units, is undercosted for its rush effect and statline. Suggestions include increasing cost to 2P, or changing its statline to 2/2 (which makes it a little easier to get banished).

Muttonmorphosis is a very soft removal and while its transformation effect is situationally useful, it usually ends up as a worse alternative compared to other 3 cost removal spells. I suggest changing the cost to 3P (increase splashability) or to 2PP.