During the declare attackers step of your opponent's combat phase, after they're done declaring their attackers, you may choose to declare Party Crasher as an attacker
Urtet, Remnant of Memnarch I've been a fan of the Myr creature type for years and even had a Karona, False God deck built around Myr
Each Core Set 2021 Collector Booster Pack contains 2 foil rare/mythics (30% chance of upgrade to foil extended art), 1 non-foil extended art rare/mythic (possible buy-a-box card), 1 non-foil rare/mythic special treatment card (showcase, alt-art/alt-frame, or borderless planeswalker), 1 foil special treatment card (showcase, alt-art/alt-frame, or borderless planeswalker of any rarity), 2 non-foil showcase or alt-art/alt-frame (common or uncommons), 1 foil showcase common or uncommon, 2 foil uncommons, 4 foil commons or lands (basic or dual), 1 foil showcase basic land, and 1 foil double-faced token.
Therefore, any opportunity to draw more cards in a mono-white deck is usually worth considering