Absolute Virtue Adelbert Steiner Aerith Gainsborough Ambrosia Whiteheart Ashe, Princess of Dalmasca Bahamut, Warden of Light Beatrix, Loyal General Cecil, Redeemed Paladin Choco, Seeker of Paradise Cid, Timeless Artificer Cloud, Midgar Mercenary Cloud, Planet's Champion Cloudbound Moogle Coeurl Delivery Moogle Dion, Bahamut's Dominant Dwarven Castle Guard G'raha Tia Gaelicat Garnet, Princess of Alexandria Giott, King of the Dwarves Hope Estheim Hydaelyn, the Mothercrystal Joshua, Phoenix's Dominant Judge Magister Gabranth Lightning, Army of One Magitek Infantry Minwu, White Mage Noctis, Prince of Lucis Phoenix, Warden of Fire Rinoa Heartilly Rosa, Resolute White Mage Rufus Shinra Serah Farron Snow Villiers Squall, SeeD Mercenary Stiltzkin, Moogle Merchant Summon: Alexander Summon: Choco/Mog Summon: Knights of Round Summon: Primal Garuda Tidus, Blitzball Star Venat, Heart of Hydaelyn Weapons Vendor Yuna, Hope of Spira Zack Fair Zidane, Tantalus Thief

Theres also some small overlap between self-mill and counters decks, as seen with Amzu, Swarm's Hunger or Centaur Vinecrasher, so I imagine quite a few decks are happy to host Obsessive Skinner
Jawbone Duelist Jawbone Duelist is very solid in decks like Standard toxic/poison, combining the toxic ability and double strike
Umbra armor's effect is applied no matter why the enchanted creature would be destroyed: because it's been dealt lethal damage, or because it's being affected by an effect that says to "destroy" it (such as Nekrataal's triggered ability)
(To mill a card, a player puts the top card of their library into their graveyard.) There is no line Jon Irenicus would not cross to regain his lost immortality
Scry 1s not a throwaway either