Walking Ballista will almost always start with at least the minimum two counters it needs to perform the loop, but might be larger in a longer game
By banishing opposing characters with low strength, she lets players rapidly accumulate lore using her high baseline stats

Scientists Abandon Attachments Action News Crew Adventurer's Airship Agna Qel'a Agonasaur Rex Airship Crash Alpharael, Dreaming Acolyte Altanak, the Thrice-Called Ancestral Reminiscence April, Reporter of the Weird Artist's Talent Ashling, Rekindled Avishkar Raceway Awaken the Honored Dead Bandit's Talent Baron Strucker, HYDRA Overlord Basri, Tomorrow's Champion Bellowing Crier Boosted Sloop Borrowed Knowledge Boundary Lands Ranger Brass's Tunnel-Grinder Broadside Barrage Byway Barterer Calamitous Tide Canyon Crab Capital City Captain Howler, Sea Scourge Carlo, Suave Schemer Case of the Crimson Pulse Casey Jones, Vigilante Chandra, Spark Hunter Charging Strifeknight Charming Scoundrel Chart a Course Chitin Gravestalker Cid, Timeless Artificer Clamorous Ironclad Clive, Ifrit's Dominant Collector's Vault Colossus of the Blood Age Cool but Rude Data Scrubber Demand Answers Detention Chariot Discerning Peddler Doc Ock's Henchmen Does Machines Dreadwing Scavenger Duelist of the Mind Emet-Selch, Unsundered Fear of Missing Out Fearless Swashbuckler Flamecache Gecko Flaring Cinder Focus the Mind Fuel the Flames Fugitive Codebreaker Furtive Courier Gallant Strike Galvanic Giant Geyser Leaper Giott, King of the Dwarves Glacial Dragonhunt Goben, Gene-Splice Savant Grab the Prize Gran-Gran Greasewrench Goblin Greed's Gambit Green Goblin, Revenant Gristle Glutton

However, its going to come at a cost, especially in prerelease formats where the prize race is so tight
Geistflame Reservoir This artifact is another one to add to the spellslingers arsenal, alongside Fireminds Research, Primal Amulet and Sphinx Bone Wand