Me0203: The murloc is a little busted IMO. I like the Voidmancer, but you can probably word it as "Battlecry and Shadow Combo:".

linkblade91: This only works if that particular expansion has a bunch of Shadow Spells for Druid, which might lose you points. Don't like that it's basically an infinite 3/2, but that might not be that strong? Not sure.

AeroJulwin: Good card! Not much else to say.

BasilAnguis: I also had a Mage card with all the Combos in the back of my mind, I like your implementation. Equilibrium is a little odd, since it does nothing without the Combos, but that might be ok.

Wailor: Damn, both are pretty good! The Scribe might be better, since there's a better chance the Combos actually trigger. It's also kinda anti-synergistic, since you want the Damage BEFORE you cast the spells.

R: The issue here is that Spell Schools were introduced in FitB, which is the expansion after this card's.

Shadowfin Soulmancer has one pretty huge problem: Chronological inconsistency. You have a card that uses Soul Fragments, a mechanic from a year before spell schools existed, and combining that with spell schools. There's simply no place in the game's life that this card could be placed. It can't be placed in Year of the Phoenix because spell schools didn't exist yet. It can't be placed before then because neither Demon Hunter nor Soul Fragments existed yet. And it can't be placed after because then you'll have a card that is unusable in Standard because there's no Soul Fragment cards in the format.

Virulent Voidmaster is definitely better. It's easier to use and it doesn't have the same chronological problem that Shadowfin Soulmancer does.

Kirin Tor Prodigy is cool, although the discrepancy in power on each of the effects is a little bit off-putting. The Fire Combo effect is just blatantly much weaker than the other two.

Equilibrium has really cool flavor, but unfortunately that flavor will overlap with BloodMefist's card from the last competition. It also doesn't do anything without the Combo effects.

"but none of them is particularly good"

I disagree. I like both of these cards. I say Swift Assassin is a little bit better since it's more to-the-point on how you're supposed to use it and it's quite flavorful, but both of them are solid cards.

It seems fine. Hot Streak is going to make any Fire spell broken, and that's not really avoidable so it's best to not worry about that.

I must ask though. Is it intended to not have a spell school? If that's the case, then balance is a complete non-issue and the card is 100% fine as is.

Demonxz95 - I can't stand Vanish, so you might lose a point from me there, but I also don't play many low-cost minions so it wouldn't bother me as much in practice.

anchorm4n - I care about board presence…a lot :( All of my decks seek to hit the board, so this could be pretty painful in my own experience. What about something like "Fire Combo: The next one you play this turn costs (1)." That way the other spell goes back to full cost; that would allow you to readjust the base spell more favorably, and mitigate a crazy Hot Streak turn.

Nirast - I'll be honest: I don't like either one. Healing Hail is an okay play on Healing Rain, but the flavor is very weird (you're being pelted with ice-rocks; why is it healing you?). Hail Storm is just Blizzard with extra steps. I'm not sure if either of them would find a home somewhere.

R - A reverse-Meteor that can also go face if you want it to? That sounds super good. I personally don't feel like Fire Mage needs more face-damage spells: it needs to be encouraged to actually use its board for once.

Wailor - Swift Assassin being connected to Poisons and thus gaining Poisonous is perfect flavor, so I would choose that one. The Scribe is wonky and redundant when we already have the simple-and-clean Lab Partner.

BasilAnguis - I like the version you posted in Discord, with the "Frost Combo: Gain 5 Armor." A nice connection to Ice Barrier, the bold text flows nicely, and you probably don't need the Prodigy to Freeze someone because you just played a Frost spell (and thus did it already).

AeroJulwin - It's okay. It's a little better than Blessing of Kings, but I don't know if it is worth running in one's deck.

Me0203 - The Soulmancer is naturally comboed with Soul Shear, but that's kind of it. The DH doesn't have many worthwhile Shadow spells; not like the Warlock does. While I like Soul Fragments more, the Voidmancer might be more viable overall.