As a general rule, when a card is good, you should probably have four of them

Song Amber UC 30/204 Recovered Page Item Amber UC 31/204 Webbys Diary Item Amber UC 37/204 Gwythaint Savage Hunter Char Amethyst UC 43/204 Iago Stompin Mad Char Amethyst UC 47/204 Duckworth Ghost Butler Char Amethyst UC 48/204 Nibs Lost Boy Char Amethyst UC 53/204 Nana Canine Caregiver Char Amethyst UC 57/204 Olaf Helping Hand Char Amethyst UC 58/204 Merlin Completing His Research Char Amethyst UC 64/204 Performance Review Act Amethyst UC 68/204 The Great Illuminary Abandoned Laboratory Loc Amethyst UC 76/204 Flintheart Glomgold Scheming Billionaire Char Emerald UC 78/204 Hook Hand Unexpectedly Friendly Char Emerald UC 79/204 Kaa Secretive Snake Char Emerald UC 80/204 Emily Quackfaster Level-Headed Librarian Char Emerald UC 81/204 Flynn Rider Spectral Scoundrel Char Emerald UC 82/204 Bellwether Master Manipulator Char Emerald UC 97/204 Malicious, Mean, and Scary Song Emerald UC 99/204 Inscrutable Map Item Emerald UC 101/204 Blessed Bagpipes Item Emerald UC 104/204 Ares God of War Char Ruby UC 111/204 Katrina Van Tassel Rosy-Cheeked Lass Char Ruby UC 113/204 Beast Aggressive Lord Char Ruby UC 115/204 Tinker Bell Temperamental Fairy Char Ruby UC 119/204 Goliath Guardian of Castle Wyvern Char Ruby UC 126/204 Mulan Standing Her Ground Char Ruby UC 131/204 Time to Go

Sisus Evasive protects her from most challenge-based board removal, but her low stats make her susceptible to popular staples like Steels Strength of a Raging Fire, Rubys own Brawl, or even an opposing Daring Visitor
If you manage to play three Action cards in a single turn, you can play Lilo for freejust like how she wrecks castles without mercy
Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to a creature may become lethal if Eye of Nidhogg becomes attached to it or unattached from it during that turn
Once per turn, you may turn a card with an inkwell symbol from your hand into face-down ink, becoming a resource that you can turn sideways to summon characters You use 60-card decks in Constructed, 40-card decks in Limited, and the official website has an excellent "how to play" section