Now that we know our Carrots from our Group Hug, let's discuss some Sticks! Both are essential if we want our wary allies and merciless opponents to respect us. Respect is key, it is that seed of doubt in our opponent's mind as to what we are capable of. It makes them fear causing us to use our resources, because when we do we go Scorched Earth. We don't start things, but we do finish them. You get the idea.
Always aim to get others to handle the threat for you, use that Table Talk as a resource of its own, but when someone decides you are the target do not let them get away with it without pain. Also, take note that many of the cards in the removal category are modular cards. That is key for this deck - you are aiming to create elaborate decision trees and then pick the right branch.
Mass Removal - When everyone has effectively infinite cards, and thus is using all their mana every turn, Bounce is almost as strong as Hard Removal. When you add in that our win condition is often predicated on filling our opponent's hands, Bounce is clearly superior. Our mass removal is focused on bounce, as is our single target removal.
Cyclonic Rift - The second best card in EDH behind Sol Ring. It's an inherently unfair card, my play group doesn't like to ban anything but I get the appeal.
Evacuation - Instant speed is your friend. This is probably your second strongest mass removal spell behind Cyclonic Rift. Sometimes it is superior, because picking up Kami can be desirable.
Engulf the Shore - This is an underrated sweeper. Draw-go is a lifestyle, and this lets you keep living it. Definitely the worst of our sweepers.
Oblivion Stone - this is our only hard removal. This still let's us play draw-go, and it makes everyone play all wonky like which can be good or bad. Also a Trophy. This card has a very high ceiling but also a very low floor, as it can draw a lot of hate. If Wizards ever prints an instant speed bounce all non-land permanents it will get the nod, but for now there are Evils we must live with.
Sunder - I am a complete Ass. I typically play this as a 5 drop if someone is land-ramping out of control early game, or if I have an active Viseling effect. I don't like to use it if I have no way of pushing the game forward, however. No one wants to play that 3 hour game, I'd rather just concede than be That Guy.
Meekstone - This card is so innocuous but has gotten me out of sooooooo many jams. And it's a Trinket!
Bounce and Board Interaction - We need some ways to punish our foes. As I mention above, Bounce is practically removal when cards are infinite. This does of course improve peoples options and general card quality, but oftentimes a threat is a threat is a threat is a threat.
Fatestitcher - A little proactive, so you need to know when your opponent is gunning for you before they swing, but this little guy can really stall that Voltron player who never drew his Greaves.
Capsize - No infinite mana means no one sided instant speed Upheaval, but a re-useable answer is still great. Probably our strongest Bounce spell.
Crystal Shard - In a similar vein as Capsize, re-useable Bounce is great. This often acts as a Tax effect for our opponents, but mostly is used as a self-bounce for cards like Archaeomancer looping into Cyclonic Rift.
Pithing Needle - First off, its a Trinket. Secondly, it's just plain good. Handles a lot of threats that we can't otherwise handle, notably commanders and Planeswalkers. I play with a Scion of the Ur-Dragon player every week, and this is my best friend.
Maze of Ith - I finally acquired a pair of original The Dark Maze! I am in love with the card, Kami is the perfect fit for it. This card is just so frustrating to try to deal with.
Stack Interaction - The true meat of the Mono-Blue archetype. You need to be very stingy with what you counter. The threat of counter magic is often much more powerful than counter magic itself. I typically only counter a spell that is going to cause me to lose the game or set me back so much that I don't believe I can recover. I also typically don't counter symmetrical board wipe type effects unless I am wayyyyy ahead. That being said, even if you don't plan to counter the play, always withhold the right to, and make them sweat a bit. Vanquish your foes with well timed Permission!
**Counterspell - Old faithful herself. Need I say more?
Arcane Denial - Cantrips and gives our opponents the option to draw more. I find that it takes the sting out a little, plus who cares if they draw from 8 to 10 cards?
Forbid - This is just silly. I mean really, when you draw 2 a turn starting turn 2, this is not fair. The only 3 mana counter we run (for now).
Foil - I don't know why more people don't play this card. It's really easy to hold up, and easy to hardcast if needed. Being able to surprise your opponent while in a "Vulnerable" position is what makes this an all-star.
Hybrids - These cards are the true face of this deck. They allow you to have an answer for anything at any time, which is Crucial to being a shifty little Fat Guy.
Venser, Shaper Savant - This guy literally does it all, including "countering" un-counterable spells. He often feels like a two-for-one, as he can easily bounce some critical piece across the table and chump whatever threat caused you to vomit him out. Can also be re-bought with Crystal Shard.
Unsubstantiate - This is a 2 mana Venser without the body or quite as many targets. Still strong, I would play this over vanilla Counterspell if I had to choose.
Twincast - I mentioned this above in "Copies", but Twincast really does so many things. Double up on your Bounce spell, copy a Counterspell, this is like a choose your own adventure spell.
Cryptic Command - I mean, what is there to discuss? This is THE modular spell. Just run it and never look back.
Mystic Confluence - I view this as Cryptic Command #2, and it might even be better because the fail safe is a draw spell. This can act as a targeted Board Wipe, a counterspell, a draw spell, or a combination. Run it.
Muddle the Mixture - A counterspell and a tutor. I run it in every Blue deck I make.
Turnabout - As mentioned in "Ramp" block, Turnabout can save your butt in a pinch.
Notable Exclusions
I have been playing this deck for years. You will probably have ideas from other Mono-Blue decks that you will suggest, and I absolutely encourage you to do so! Here are some cards that I have tinkered with or used to be considered worth a slot that I no longer feel the same way about, or that I would like but do not currently own.
Disallow - I may add it once I get my hands on one. What to cut has been making me drag my feet, but countering abilities is too good to pass up.
Glacial Chasm - I think I need to find room for this, I play it in many of my decks and I just see the value continually rising. Sometimes you drop this card and can coast to an easy win.
Snap - I may add, untappers are stronk. It's a balance between what modes I want on my two mana Bounce.
Reality Shift, Pongify, Rapid Hybridization - I don't know, I just never got excited about these. We'd rather just have a Bounce spell.
Telekinesis - I want one, I'd add it if I find one.
Distorting Wake, Crush of Tentacles, Turbulent Dreams, Whelming Wave - All existed in this deck at different points. Inferior to our current options in my opinion.
Time Stop - Very powerful, and many modes, but VERY expensive for what it does. I played it awhile and it felt very, very clunky.
Swan Song - I really should find a spot for this, it's just so versatile, but it's tough to find a counterspell to cut.
Glen Elendra Archmage - this will go in, someday. I don't own one currently. But wow, just one of the strongest counters possible, it really creates some states where you can't lose.