I assume I was subconsciously influenced by games I liked
Use a sturdy cardboard box, organize your cards into neat rows, add dividers where needed, and fill any empty space with packing material so the cards do not shift during transit
Images of the Past Images of the Past is a really fun way to cash in on some ETB effects without paying a lot of mana
Budget-friendly to buy, cheap to play, works with big creatures and even better with small fodder you can't go wrong with Skullclamp
Here's a list of the cards that are reprinted in M21: Baneslayer Angel Grim Tutor Ugin, the Spirit Dragon Azusa, Lost but Seeking Runed Halo Fierce Empath Tormod's Crypt Quirion Dryad Rain of Revelation Jeskai Elder Containment Priest Rewind Faith's Fetters Grasp of Darkness Radiant Fountain Lorescale Coatl Solemn Simulacrum Cultivate Heroic Intervention Massacre Wurm Temple of Epiphany, Temple of Triumph,Temple of Malady, Temple of Mystery, Temple of Silence Fabled Passage Furious Rise Riddleform Goblin Arsonist Vryn Wingmare Duress Ranger's Guile Defiant Strike Glorious Anthem Battle-Rattle Shaman Colossal Dreadmaw Scavenging Ooze Palladium Myr Kitesail Freebooter Volcanic Geyser No Fetch Lands Yes, I know you're really desperate to get your hands on new fetches, especially with the prices being sky high