A melded creature like Brisela, Voice of Nightmares doesn't have a mana cost, but it does have a mana value (which is )
I expect that Kamigawa: Neon Dynastys impact will be felt in Cube more with regard to these themes than individual cards, but there are absolutely some individual cards worth discussing
For more on the number of cards in different formats, see How Many Cards in an MTG deck
Samwise Gamgee Combo (3.5% of the Winner's Metagame) 4 Cauldron Familiar 4 Gilded Goose 4 Samwise Gamgee 4 Viscera Seer 4 Birthing Ritual 4 Chord of Calling 4 Verdant Catacombs 4 Windswept Heath 3 Wall of Roots 2 Boseiju, Who Endures 2 Overgrown Tomb 2 Temple Garden 2 Orcish Bowmasters 2 Young Wolf 2 Thoughtseize 1 Dryad Arbor 1 Forest 1 Godless Shrine 1 Lush Portico 1 Underground Mortuary 1 Grist, the Hunger Tide 1 Wooded Foothills 1 Sylvan Safekeeper 1 Haywire Mite 1 Nurturing Peatland 1 Swamp 1 Brightglass Gearhulk 1 Skyclave Apparition 3 Force of Vigor 2 Fatal Push 2 Veil of Summer 2 Thoughtseize 1 Drannith Magistrate 1 Suncleanser 1 Crystal Barricade 1 Endurance 1 Enduring Innocence 1 Collector Ouphe Samwise Gamgee Combo is a creature-based combo deck that revolves around the trifecta of Samwise Gamgee, Viscera Seer, and Cauldron Familiar
If you're looking to just play one of these decks without upgrading, but want to compete at higher levels, Counter Blitz is your best shot
Token-centric decks like Baylen, the Haymaker make fantastic use of it as a way to pump out hordes of 1/1s