Hey, a couple weeks ago I posted a little analysis on what I thought about black cards in Invasion booster draft. Now I thought I would continue on with Blue.
Blue is a very strong color, pairing well with either black or white's cards. U/B is a very aggressive deck with Urborg Drake, Urborg Phantom, Urbord Emissary, Duskwalker, Fairie Squadron, Vodalian Zombie, Tower Drake, Tidal Visionary.
U/W is more of a control deck using tappers, Obsidian/Crimson acolyte + Tidal Visionary combos (VERY mean), and other things while their skies (tower drake, glimmering angel, razertooth griffin, and Faire Squadron) take care of the job.
Well, here's what I think about the Blue cards:

Barrin's Unmasking
4
It's at best a boomerang, at worse a rescue. Who played those in draft? Still, it fits in the sideboard well in an aggressive deck.


Blind Seer
7
A hill giant at worse, this guy with the right deck can wreck. It can make your djinns be big, make weavers count for any creature, and protect from black destruction or other protection.


Breaking Wave
6
Eh...too weird to really rely on. Still, it has potential. If anybody's seen a limited play where this has done well, please post it or e-mail me, I'd love to hear it!


Collective Restraint
5
Kinda like Propaganda, it's pretty good, but not amazing.


Crystal Spray
2
You'd have to find a good way to play this, but then again, it can thin your deck.


Disrupt
3
Fits in sideboard well, but nothing really to use it on.


Distorting Wake
9
Wow, return all their creatures and attack for huge ammounts. This kinda works like Plauge Wind. Still, if your attack doesn't win it for you, they may recover quickly.


Dream Thrush
7
I've never really played this card, but I've heard amazing things. Mana efficiency for you, mana screw them, landwalk, ect. He makes your Vodalian Serpents attack!


Empress Galina
5
The only time I had a chance to play her, I took Fairie Squadron instead. A 1/3 for 5 sucks, so she'd only remain in your sideboard. She does get rid of the occasional Dragon or what not, but the chances of seeing a Legend that doesn't have protection from legends is very very low.


Essence Leak
6
Great sideboard card, and it can replace most of your non-creature cards, all of your blue ones.


Exclude
6
Better in U/W, but depends on your deck. The only time I've played it was in an agressive deck where it didn't get played once.


Fact or Fiction
9
Amazing card drawing, just watch it in a slow deck, you might deck yourself. :)


Farie Squadron
8
3/3 F-L-Y-E-R-S A-R-E G-O-O-D.


Mana Maze
2
Doesn't do much, unless you have Blind Seer and instants to play on their upkeep.


Manipulate Fate
5
Great with Wash Out against 2 different colored creatures. Good with Reckless Spite against black, plus the whole bit.


Metathran Aerostat
7
2/2 flyers are good, and the ability is better than you think. I blocked and killed a creature with it, then used its ability to play Tower Drake and return it to hand. :)


Metathran Transport
5
A nice defensive creature, but the ability isn't that great.


Metathran Zombie
4
Overrated, only good in defensive black decks. Your U/B deck would probably only be defensive if you have these. Still, your call.


Opt
4
I don't really like it, but it's a 1 mana cantrip, and it will always but usefull.


Phantasmal Terrain
3
Chubby, but I've heard somebody at a tourney I played won with this card, but I don't know how. Hmmmm....


Probe
5
I've played U/B with 8 noncreature cards, 2 of these in sideboard, and won undefeated. Still, It really depends on your deck, plus a lot of people like it.


Prohibit
5
Pretty good, but only if that's what you wanna do. Don't play it agressively.


Psychic Battle
1
Uhhhh.......


Rainbow Crow
7
It's fun to say rainbow crow. 2/2 flyers are good, but it is slightly overcosted. The ability protects it from a lot though.


Repulse
7
My opinion is why play this instead of exclude, but I'm more and more learning. Bouncing is great early in a beaty deck, and no card disadvantage.


Saphire Leech
7
I've passed this before, I don't remember for what. A 2/2 Flyer for 2 is good, but the ability hurts.


Shimmering Wings
6
I don't really like creature enchantments besides shackles, but a lot of people really like it. You decide.


Shorelind Raider
8
2/2 for 3 is surprisingly good, and you'd be surprised how much this guy will help you out!


Sky Weaver
9
I love all the weavers, 2/1 for 2 is just beatalicious. The ability is REALLY good too.


Stormscape Apprentice
9
Tapping is great, just good. This guy is pretty speedy too. The black ability isn't amazing, but worth playing.


Stormscape Master
10
All the masters are great. Protection is great, especially if you can choose which creature gets it and what color he's protected from. If you can set up a great defense, the black ability will just win it for you.


Sway of Illusion
4
Cantrip, but it can be really great if you draw it late to remove 3 land and improve your draws. Still, it sticks in your hand if you draw it early, and that can't be good.


Teferi's Response
2
Draft it, people want it! Kidding. Just see the look on your opponents face when their Keldon Necropolis is nuked!!


Tidal Visionary
9
1 drop that works with protection, black's nuke, acolytes (mean), weavers, djinns, etc. Take it!!


Tolarian Emissary
6
Ehh...Iffy, nice sideboard, decent body.


Tower Drake
7
2/1 flying for 1 is great, even in black. The ability is awesome. Watch out for zap and cursed flesh if playing u/w.


Traveler's Cloak
7
Cantrip Cloak of Mists...I thought nothing could be better when playing masques block. For some reason, this bad boy was multiples in my sideboard.


Vodalian Hypnotist
8
Great ability!! Don't even touch if it you're playing U/W though.


Vodalian Merchant
6
I would have loved it if it were 2/1 instead, but that's not blue's style. Pretty good ability, but I don't know...


Vodalian Serpant
7
Don't play w/o kicker, a 6/6 wall is great. If your opponent is blue, all hell is breaking loose.


Wash Out
10
Yep.


Well-Laid Plans
4
Playable if you have 4 tidal visionary's, and good for mirror if you have more evasive creatures.


Worldly Counsel
3
I just don't like cards like this, your call.


Zanam Djinn
9
Great Djinn, big big flyers are great.


That's about it, hope you enjoyed. This is my point of view, play and decide what you think. Good Luck!