Death and Taxes (Mono-white)
If they don't have Cataclysm, or a nut draw of denial vs a bad draw from me, this matchup is basically a cakewalk. Needle stops Wasteland or Vial. Rishadan Port is pretty laughable aside from the first turn or two and then we just go way over the top of them. Cataclysm hurts a lot though. Warping Wail helps with that, as prior to that existing, I wouldn't bring in countermagic for this matchup so would be stone-cold dead to Cataclysm. Warping Wail is a house (on paper) vs this matchup, although I have yet to actually play the matchup since putting Wails in. It kills almost anything in their deck, counters Cataclysm or just provides a blocker/slight ramp.
Delver
I don't find these matchups to be all that bad. I haven't played against it nearly as much lately though. RUG Delver can be somewhat rough, especially if they're splashing Black since DRS gets around Glacial Chasm and Abrupt Decay can screw up your needles. BUG is really rough with Hymns, but winnable. UWR Delver is a lot faster, but they're all winnable matchups as long as you can protect for wasteland. You just have to be careful with timing and sequencing to get around Dazes.
Wasteland
Pithing Needle. Crop Rotation also helps against this, but I love Pithing Needle.
Eldrazi Stompy
This deck is why I think I'm switching to Bant so I have access to Terminus and Swords to Plowshares. This matchup is just really rough. Chalice doesn't hurt so much but they can put in way too much damage too quickly and that plus Wasteland just really fucks you up unless you can land an early titan off Show and Tell, or Platinum Emperion which most configurations won't be able to deal with aside from a slow ticking Ratchet Bomb which gives you loads of time. My friend is running Duplicant though as super awesome tech which totally bungs that plan (he runs it largely for Show and Tell in general).

