Memory Lapse is the best suited counterspell for Xanathar
As for mechanics, the card Paladin of Predation shows off a brand new one, Toxic , a new way of using poison, where both damage and counters get dealt
You would be wrong, but we encourage you not to debate this in front of Yargle
Thus, the card is maximally useful against removal with an odd casting cost
If you pay one White mana and tap them you can sacrifice an Artifact to Search your library for an Artifact card with mana value equal to 1 plus the sacrificed Artifacts mana value
They both fit into the same deck -- basically any deck that runs multiple 1cmc creatures like Weathered Wayfarer and Giver of Runes -- and I'd run both in those decks, but Ranger-Captain is even better than his younger version