Alright, so here's what I see from looking at your deck.
1. Money is not an issue.
2. Your answers have to be low mana, preferably 1 or 2 mana. 3 mana has to do something really special.
3. This deck is highly dependent on its artifacts.
Now normally, if artifacts are giving you a hard time, I'd recommend
Seeds of Innocence, but this will likely hurt you more than your opponents. I'm on the fence about
Vandalblast. In cEDH, I have never seen anyone
overload Vandalblast, the cost is just too high. But with all the ramp you have, it might be feasible. I personally prefer
Shattering Spree, and it will also work with Yidris. If you cascade into
Shattering Spree, you can still replicate it (it is an additional cost, not alternate, like
Vandalblast).
You should also consider some of the following.
Caustic Caterpillar: you can activate it at instant speed. However, if
Cursed Totem is prevalent in your meta, don't use
Caustic Caterpillar.
Flusterstorm: designed for storm decks, you can counter those stax effects for one mana.
Flusterstorm counts the number of spells played (both yours and your opponents) so they'll have to pay two mana to counter both copies (or more, if they had cast other spells that turn).
Paradox Engine: you use lots of artifacts that are waiting to be untaped.
Paradox Engine will help get around tapping effects. The downside... It's 5 mana, and that might not be an option if you're heavily staxed.
Remember: you can combo off quickly. For many stax effects, you'll only need them
gone for one turn. I've assumed that most of these effects are artifacts. If creatures are giving you trouble,
Toxic Deluge and
Pyroclasm will eliminate most hatebears.