This list started with what I really remember being truly iconic from the 2015-2019 Modern Era. I'm not opposed to cards printed after this time, but the Jund and Twin Era is really what I have in mind.
My goals are to create tight, interactive games.
I've avoided the outright combo decks and decks like Infect, Affinity and Tron that are hyperfocused on tribal cards that are commonly considered parasitic design. This is mostly due to the 4 player space of the cube.
I've taken care to avoid cards that completely hose a particular strategy. Permanent sources of Hexproof, Indestructible and Protection are frowned upon. Not too fond of Creeping Corrosion and Rest in Peace Effects. Single Target answers are common, though. I'm also avoiding Lifelink where possible. Wurmcoil and Nighthawk are iconic, though.
When drafting this cube, a player may include 2 identical Onslaught/Zendikar fetches of their choosing when adding basics. These must be chosen prior to the first game of a set and cannot be sideboarded. Basics can, however

General themes and archetypes:
White: Go Wide Creatures + General Utility.
Blue: Control, Spells Matter.
Black: Midrange, Crime/Morbid matters.
Red: Aggro, Prowess.
Green: Efficient Creatures and Ramp