Ashcoat of the Shadow Swarm Ashcoat of the Shadow Swarm Freya Crescent Greasefang, Okiba Boss Ink-Eyes, Servant of Oni Karumonix, the Rat King Lord Skitter, Sewer King Marrow-Gnawer Nashi, Moon Sage's Scion Nashi, Moon's Legacy Nashi, Searcher in the Dark Old Flitterfang Rat King, Pale Piper Rat King, Verminister Splinter & Leo, Father & Son Splinter, Aging Champion Splinter, Hamato Yoshi Splinter, Radical Rat Splinter, the Mentor Vren, the Relentless Wick, the Whorled Mind
A simple, all-purpose creature answer is something blue cards usually have less access to
Though this Special Illustration Rare version is the most valuable, its standard, uncommon variant is just $0.11 , so if you arent fussed about getting the most spectacular looking card, it wont break the bank to get multiple copies of Cassiopeia
Tri-Brigades play style revolves around loading the Graveyard with monsters and then banishing them with Tri-Brigade Fraktall
Retraced Image is literally blue ramp in mono-blue, but less relevant otherwise, as you wont always have another Island to put into play
Griselbrand gives big life swings, as does Sphinx of the Steel Wind however both are the preserve of combo style decks