Your safest bet for long-term value would undoubtedly be PSA 10 copies of these cards - anything below that is extremely risky

FIGHT TO SURVIVE IN A HOUSE OF NIGHTMARESDare to enter Duskmourn, a plane-enveloping House that sets the scene for your opponents greatest fears to come to life FRIGHTENINGLY GOOD FINDSCollector Boosters are a shortcut to the coolest cards in a set, with packs full of Rare cards, shiny foil cards, and special alt-art, alt-frame cards HORRIFY YOUR FRIENDS IN STYLECollect more hard-to-find Duskmourn: House of Horror cards with 5 cards of rarity Rare or higher and a total of 5 alt-border cards in every Collector Booster COLLECTOR BOOSTER-EXCLUSIVE TREATMENTSCollector Boosters are the only place you can find certain coveted card styles, including the possibility of extended-art cards or even a card with the special Textured Foil Double Exposure treatment COLLECTOR BOOSTER BOX CONTENTS12 Duskmourn: House of Horror Collector Boosters, with 15 MTG cards in each pack Beyond Boosters vs
Some collectors even keep a favorites or trade binder apart from their main collection
I stumbled onto an article on Channel Fireball that talked about how much fixing you needed to reliably cast spells on certain turns and with certain mana costs (C or CC or CCC, etc)
In game terms, Scrooge McDuck has a 5 Ink cost, 3 Strength and 5 Willpower, along with 1 point of Lore