Need Help: Talrand, Sky Summoner, EDH.

Really quick & dirty- OUT:

Peer through depths- too easy to whiff

Psionic Blast- spot removal is bad in EDH but it has its place- the things you want to spot remove rarely have 4 toughness

Spell Pierce- Conditional counter, and 2 mana is really easy to come by in EDH. Occasionally you'll hit someone's T1 Sol Ring but more often than not you'll just wish this was something else.

Force Spike- nobody's breaking their balls to come by 1 spare mana in EDH. This is an opinion, but I think that any counterspell that can be turned off with mana is bad in EDH.

Spell Snare- Also conditional, you could go the whole game without seeing anything worth spending it on

Flash of Insight- way too expensive for what it does

Archetype of Imagination- when you only run 8 creatures, it really doesn't matter if your creatures or your opponents' creatures fly

Gitaxian Probe- low-impact cantrips are not good enough for Talrand in my experience. There are more than enough good blue cards- you don't need to use Probe to run a 98 card deck for lack of a good 99th.

Serum Visions, Sleight of Hand- same argument as G Probe. These don't dig very well like Ponder & Preordain do. If you want a better cantrip, try Portent.

Talrand's Invocation- meh. I can see keeping it if drakes are going to be your win condition, but it looks like giant fat beaters are your wincon. This just doesn't do much for you at its cost.

Treasure Cruise- a lot better draw options in this format.

Goliath Sphinx- this wants to be Inkwell Leviathan or Sphinx of the Final Word

Colossus of Akros- bad and shitty

Day of the Dragons- Another one that's okay (and super flavorful) for the drake wincon, but i think you need to specialize towards one of these wincons. If you're keeping the giant beaters, this should probably go.

Favorable Winds & Grav Shift- see Day of the Dragons

Unsummon, Vapor Snag, Pongify, Rapid Hybridization... I can see running some of these, since you do want to be able to remove a threat, but there's no reason to pack your deck full of creature spot removal when it's arguably the thing that blue does worst.

/r/EDH Thread