The follow-up Modern Horizons 2 was even worse in this regard, but it's safe to say the first Modern Horizons set turned multiple formats on their heads, and they've been stuck upside-down ever since
One thing they came up with was trying to encourage decks that used a lot of cards from the set
Plague Nurse Arguably one of the prettier cards from this set, Plague Nurse does two toxic damage
Most evilly (and boring, in my opinion), you can combine Squirrels with Opposition
It draws equal to your biggest power, and note that's not targeted, but just when it resolves, and then instant speed is great too since you can do it when it's removed to draw or just to dig or EOT to just use your mana
Omniscience [Best Game Ending Enchantment] Magic: The Gathering is largely defined by its mana economy