In particular, I was using the entire 15 cards of my side deck in the ABC mirror match depending on who started
Amethyst Emerald has some nice rush characters that can pop damage, then dropping Go Go will once again net you some lore for just two ink, with a body on board that's Evasive for survival, ready to be bounced and played again for even more lore gain

Academic Probation Arachnus Web Archon of the Triumvirate Arrest Avacyn's Collar, the Symbol of Her Church (playtest) Azorius Arrester Azorius Justiciar Bound in Gold Braided Net Clarion Conqueror Collector Ouphe Cursed Totem Damping Matrix Deadlock Trap Demotion Desert's Hold Detainment Spell Detention Vortex Disruptor Flute Dovin Baan Drana and Linvala Edifice of Authority Encrust Faith's Fetters Gelid Shackles Gobsmacked Hold for Questioning Ice Cage Inaction Injunction Intercessor's Arrest Interdict Isperia's Skywatch Karn, the Great Creator Katabatic Winds Koma, Cosmos Serpent Koma, Cosmos Serpent Krasis Incubation Lavinia of the Tenth Lawmage's Binding Linvala, Keeper of Silence Linvala, Shield of Sea Gate Lost in Thought Lyev Decree Lyev Skyknight Martial Law Mythos of Vadrok Nahiri's Binding New Prahv Guildmage Null Rod One Thousand Lashes Petrified Hamlet Petrify Phyrexian Revoker Pithing Needle Planar Disruption Prison Sentence Prison Term Realmbreaker's Grasp Scheming Fence Seatower Imprisonment Secure Detention Serra Bestiary Sharkey, Tyrant of the Shire Sorcerous Spyglass Soulsworn Spirit Stasis Cocoon Stony Silence Stormcage Containment Facility Stuck in Summoner's Sanctum Stupefying Touch Suppression Bonds Tax Collector

though best to err on the side of caution
I regret lending it to a friend, because I havent seen it since
If youre playing cheap spells like Shelter or Take Up Shield, casting multiple spells per turn is easily achievable and will give Arcee a bunch of counters