Ishkanah's Web basically says "creatures with flying and toughness less than 4 can't attack you" which is ok if you're just trying to make a smaller, wordier version of Sandworm convergence (without the free token, which you pretty much never will get with your version unless you pair with one of the red or blue force attacking cards).
What if instead it was a creature, like:
Corpse Nest Spider 2BG
Creature Spider Rare
Reach
When a creature dealt damage by ~ dies, create a token copy of it.
2/4
With Rayne, Tolarian Headmaster, I think it would be more fun if the abilities fed into each other. Like, U, tap two wizards you control: Draw a card U, Discard two cards: Counter target creature spell U, Exile two creature cards from an opponent's graveyard: Create a 1/1 blue wizard creature token with hexproof
p/t equal to the number of wizards you control
Although that works a bit better as a zombie wizard, I guess. Could change "counter/exile target creature creature spell" to "noncreature" for better flavor.
Your Mayor Fenton just seems like a bad version of Outlast. For tapping four creatures I think you could get a Gavony Township effect.
Suena might be broken for all I know, but give the power of Brago, I don't see why the effect needs a mana cost.
Remy seems a little more promising, but still doesn't seem like sufficient incentive to fill my deck with 1 power creatures. Grant Deathtouch as well and it might.
I think this is a poor mechanic to have much of in a set because it decreases surprise/tension in large numbers and does little to impact the game in smaller numbers. What if you Index 4 and they're all lands--scoop, or play a game where you know your draws are going to be dead?
"Loki's Aid" doesn't sound like a creature. What if it was "Loki's image" and was an Illusion Wizard?
Also, what if it was "return to hand" instead of sacrifice? Would be neat synergy with Loki.
I like illusions as a characteristic blue creature type. I also like creatures like illusions and shades that frequently have the same mechanical connection, although not all illusions have that drawback (Jace's Phantasm, for example)
These are all pretty good ideas. Your octopus is worse than a similarly sized & costed creature that just had hexproof instead of the ability. It's still probably a fine uncommon; I like that it's a reverse heroic trigger.
You'll probably be best off heading to the articles sub-forum for in-depth how-to's, but since you asked, cube is simply a custom draft format. That is, take some cards you already own, shuffle them up, pass out 3 sets of 15 to each player, draft as normal, then play.
Most cubes are aimed at having the most powerful cards available to the owner in the draft, so often different peoples cubes tend to converge and in these forums there lots of discussion about which cards of each color to include.
Some cubes are built around other restrictions or themes, like mimicing a draft format of the past, being multiplayer friendly, or only using common cards. Often cubes are built with highlighting specific synergies in different color combinations, like Azorius blink or golgari reanimator, etc.
Shame about the discard. Is otherwise quite a decent uncommon as a poor man's Kitchen Finks. Will be decent in limited I'm sure.
I didn't see that added cost at first, but since 4/4 for 4 plus 4 life is more than fair, and it's a free card, it's still decent at least and fairly good most of the time.
Ah, but if you change it to an "attacking matters" mechanic that shares stuff; that screams Boros...
I like this thought. How about: If the target is attacking, you may pay x to copy this spell.
Hidden Resilience WW
Instant
Target creature gets +1/+3 until end of turn Combat Cast: If the target is an attacking creature, you may pay 1; if you do copy the spell and choose new targets for the copy.
Could even work on damage, ie.
Defensive HelixWR
Instant
Deal 2 damage to target creature. You gain 2 life. Combat Cast: If the target is an attacking creature, you may pay 2; if you do, copy the spell and choose new targets for the copy.
Template question, are players ever considered to be attacking? It's clear what you are going for though.
It seems too much for me. What about:
Whenever an opponent attacks with one or more creatures, Draconian Knight fights one of them.
When Draconian Knight deals damage to a creature, it deals that much damage to that creature's opponent
Where's the torment of locusts? Odd that the cycle is two of Bolas' gods and Bolas, not his three gods or all four. (Oh, right, Locust god isn't black, so it wouldn't fit in a mono-black cycle.)
Struggle is like a decent removal spell that puts a card from your sideboard into your graveyard. Not a sideboard card you were likely to use, but still, upside.
Weird card. It rewards having access to really high levels of mana, because otherwise it's going to take awhile to profit from having 5 more 5-drops in hand. Also of course you have to know your deck really well, because if you already cycled one of your 5 5-drops it would fizzle if there are only 4 in your deck.
Probably best to get 3 3-drops and play two on turn six, I'd bet.
What if instead it was a creature, like:
Corpse Nest Spider 2BG
Creature Spider Rare
Reach
When a creature dealt damage by ~ dies, create a token copy of it.
2/4
With Rayne, Tolarian Headmaster, I think it would be more fun if the abilities fed into each other. Like,
U, tap two wizards you control: Draw a card
U, Discard two cards: Counter target creature spell
U, Exile two creature cards from an opponent's graveyard: Create a 1/1 blue wizard creature token with hexproof
p/t equal to the number of wizards you control
Although that works a bit better as a zombie wizard, I guess. Could change "counter/exile target creature creature spell" to "noncreature" for better flavor.
Suena might be broken for all I know, but give the power of Brago, I don't see why the effect needs a mana cost.
Remy seems a little more promising, but still doesn't seem like sufficient incentive to fill my deck with 1 power creatures. Grant Deathtouch as well and it might.
Also, what if it was "return to hand" instead of sacrifice? Would be neat synergy with Loki.
Most cubes are aimed at having the most powerful cards available to the owner in the draft, so often different peoples cubes tend to converge and in these forums there lots of discussion about which cards of each color to include.
Some cubes are built around other restrictions or themes, like mimicing a draft format of the past, being multiplayer friendly, or only using common cards. Often cubes are built with highlighting specific synergies in different color combinations, like Azorius blink or golgari reanimator, etc.
I like this thought. How about: If the target is attacking, you may pay x to copy this spell.
Hidden Resilience WW
Instant
Target creature gets +1/+3 until end of turn
Combat Cast: If the target is an attacking creature, you may pay 1; if you do copy the spell and choose new targets for the copy.
Could even work on damage, ie.
Defensive HelixWR
Instant
Deal 2 damage to target creature. You gain 2 life.
Combat Cast: If the target is an attacking creature, you may pay 2; if you do, copy the spell and choose new targets for the copy.
It seems too much for me. What about:
Whenever an opponent attacks with one or more creatures, Draconian Knight fights one of them.
When Draconian Knight deals damage to a creature, it deals that much damage to that creature's opponent
Struggle is like a decent removal spell that puts a card from your sideboard into your graveyard. Not a sideboard card you were likely to use, but still, upside.
Probably best to get 3 3-drops and play two on turn six, I'd bet.