At the time mill decks tended to be mono-blue or white-blue and were all about controlling the environment, using milling as a win condition once control was established
X , which was a very strong card when it was legal
Im no expert on it, so my logical starting point would be the Mono-Red deck that made Top 8 in Los Angeles designed by Patrick Sullivan
The Gateway kit is the perfect way to learn Lorcana The key is that Lorcanas Gateway Kit isnt just a bunch of cards, but instead a fully developed system that slowly builds up each players deck and options over time

Abomination of Llanowar Aesi, Tyrant of Gyre Strait Akiri, Line-Slinger Akroma, Vision of Ixidor Alena, Kessig Trapper Alharu, Solemn Ritualist Amareth, the Lustrous Anara, Wolvid Familiar Araumi of the Dead Tide Archelos, Lagoon Mystic Ardenn, Intrepid Archaeologist Armix, Filigree Thrasher Averna, the Chaos Bloom Belbe, Corrupted Observer Bell Borca, Spectral Sergeant Blim, Comedic Genius Brago, King Eternal Breeches, Brazen Plunderer Brinelin, the Moon Kraken Bruse Tarl, Boorish Herder Captain Vargus Wrath Colfenor, the Last Yew Danitha Capashen, Paragon Dargo, the Shipwrecker Derevi, Empyrial Tactician Eligeth, Crossroads Augur Esior, Wardwing Familiar Falthis, Shadowcat Familiar Ghen, Arcanum Weaver Ghost of Ramirez DePietro Gilanra, Caller of Wirewood Glacian, Powerstone Engineer Gnostro, Voice of the Crags Gor Muldrak, Amphinologist Halana, Kessig Ranger Hamza, Guardian of Arashin Hans Eriksson Ich-Tekik, Salvage Splicer Ikra Shidiqi, the Usurper Imoti, Celebrant of Bounty Ishai, Ojutai Dragonspeaker Jared Carthalion, True Heir Juri, Master of the Revue Kamahl, Heart of Krosa Kangee, Sky Warden Karador, Ghost Chieftain Karametra, God of Harvests Kediss, Emberclaw Familiar Keleth, Sunmane Familiar Keskit, the Flesh Sculptor Kodama of the East Tree Krark, the Thumbless Kraum, Ludevic's Opus Kwain, Itinerant Meddler Kydele, Chosen of Kruphix Lathiel, the Bounteous Dawn Liesa, Shroud of Dusk Livio, Oathsworn Sentinel Ludevic, Necro-Alchemist Maelstrom Wanderer Malcolm, Keen-Eyed Navigator Marath, Will of the Wild Meloku the Clouded Mirror Miara, Thorn of the Glade Molimo, Maro-Sorcerer Muldrotha, the Gravetide Nadier, Agent of the Duskenel Najeela, the Blade-Blossom Nekusar, the Mindrazer Nevinyrral, Urborg Tyrant Nezahal, Primal Tide Numa, Joraga Chieftain

Pro Tip Before you buy, make sure you scour the internet and all available databases to investigate the real scarcity of a card