Mono-Blue Terror is almost entirely blue, so your sideboard has no cards that interact meaningfully with their Counterspell suite or their Tolarian Terror/Cryptic Serpent threats, since Deglamer and Relic of Progenitus don't target creatures or counterspells. Your best plan is simply to play your normal aggressive curve, using mana acceleration from Utopia Sprawl and Arbor Elf to deploy threats faster than they can answer with Counterspell or Dispel. Avoid walking threats into open mana when possible and force them to commit removal or counters early. No sideboard changes are worth making here since nothing in the 82 nonland cards improves on the maindeck plan.