The best monsters to bring out with this are generic fusions that only need a specific Type or Attribute of monster
(Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player exiles cards with total mana value 4 or greater from their graveyard.) Illustrated by Maxime Minard Standard Legal Alchemy Not Legal Pioneer Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
However, if your opponent doesnt mind they can use proxy cards in test battles
You can change the battle position of a card on the same turn it is set/summoned (including Flip Summon)
Countermagic : Mystic Snake, Frilled Mystic, Draining Whelk Reanimation : Karmic Guide, Phyrexian Delver, Extraction Specialist Milling : Manic Scribe, Thieves' Guild Enforcer, Sage's Row Denizen Self-Milling : Stitcher's Supplier, Satyr Wayfinder, Balustrade Spy Discard : Burglar Rat, Mesmeric Fiend, Sin Collector Goading : Insufferable Balladeer, Jeering Homunculus, Vengeful Ancestor "Gain Control" effects : Hostage Taker, Agent of Treachery, Gonti, Lord of Luxury Clones : virtually all of them, though a few are decently pricey
Turn it face-down (super value if you turn off a Seal of Orichalcos this way)