Spoilers Whenever an opponent scries, surveils, or searches their library, put a +1/+1 counter on River Song
It would be a great answer to a very aggressive strategy
3 Junk Forward: Rank 3 enabler
Yawgmoth provides a similar card draw option and also incredibly relevant text for the mirror, having protection from Humans as well as being able to turn creatures that would otherwise die to removal into additional cards while shrinking opposing creatures
Aberrant Mind Sorcerer Abomination of Llanowar Accomplished Alchemist Advocate of the Beast Aether Herder Aftermath Analyst Ajani's Comrade Alisaie Leveilleur Allosaurus Rider Allosaurus Shepherd Alpha Guard Alphinaud Leveilleur Ambush Commander Aragorn and Arwen, Wed Arbor Elf Arcane Investigator Architect of the Untamed Argothian Elder Armorcraft Judge Armored Wolf-Rider Arwen Undmiel Arwen, Mortal Queen Arwen, Weaver of Hope Astarion, the Decadent Atomwheel Acrobats Attended Socialite Aurora Champion Ayara, First of Locthwain Ayara, Furnace Queen Ayara, Widow of the Realm Baeloth Barrityl, Entertainer Beast Whisperer Beast-Kin Ranger Beastcaller Savant Behemoth's Herald Belbe, Corrupted Observer Bennie Bracks, Zoologist Birchlore Rangers Blaring Recruiter Blightsoil Druid Bloodbraid Challenger Bloodbraid Elf Bloodline Shaman Bloom Tender Borderland Explorer Boreal Druid Boreal Outrider Boss's Chauffeur Bramblewood Paragon Branchblight Stalker Brazen Upstart Briarblade Adept Brightwood Tracker Caller of the Claw Caller of the Untamed Canopy Tactician Carapace Forger Cautious Survivor Celeborn the Wise Celebrity Fencer Centaur's Herald Champions of the Perfect Chance-Met Elves Circle of Dreams Druid Circle of the Moon Druid Citanul Stalwart Civic Wayfinder Cloakwood Swarmkeeper Coiling Oracle Compleated Huntmaster Conclave Guildmage Copperhorn Scout
