Surprisingly, she is the only character in the entire anime to have never lost a duel that we are aware of, even beating Yugi's record
Antler Skulkin Blazethorn Scarecrow Chainbreaker Crossroads Candleguide Dread Tiller Fang Skulkin Farmstead Gleaner Field Creeper Foraging Wickermaw Geist-Fueled Scarecrow Grim Poppet Harvest Hand Heap Doll Hoof Skulkin Jawbone Skulkin Jousting Dummy Lockjaw Snapper Lurebound Scarecrow Oasis Gardener One-Eyed Scarecrow Osseous Sticktwister Painter's Servant Pili-Pala Rattleblaze Scarecrow Reaper King Rendmaw, Creaking Nest Scarecrone Scarecrow Scarecrow Guide Scaretiller Scorn Effigy Scrapbasket Scuttlemutt Shell Skulkin Shire Scarecrow Signpost Scarecrow Sparring Dummy Straw Soldiers Tatterkite The Reaper, King No More The Swarmweaver Thornwatch Scarecrow Watchwing Scarecrow Wicker Picker Wicker Warcrawler Wicker Witch Wickerfolk Indomitable Wickerfolk Thresher Wild-Field Scarecrow Wildfire Wickerfolk Wingrattle Scarecrow Wreckage Wickerfolk

As far as strategy goes if you are using more than one Espeon in your deck or another Eevee-evolution in your deck it would only make sense to have Espeon in your deck so that that other Eevee evolution would have 20 more hp
The overall strategy of the deck is to stall long enough for your opponent to deck out
Here are a handful of useful cards that require you to discard, so you need cards in your hand to use these to the fullest: Born to Drive, Team Avatar, or Abolish
[G][C][C] Shroom Drain: 80 damage