Cascading into suspend spells like Living End and Ancestral Vision has been a valid strategy ever since the cascade mechanic was born back in 2009. Even in today’s Modern, numerous such strategies exist. However, the most simple, straightforward and effective of them is to cascade into Crashing Footfalls.
The key to the deck is that Crashing Footfalls is the only nonland card with mana value of less than three. This means that your cascade spells will always cast Crashing Footfalls, and thus generate a massive army for the price of three mana.
However, just because you can’t throw any old Lightning Bolt or Counterspell into your deck doesn’t mean that you can’t access cheap plays. In fact, there are at least four places you can look for useful spells to round out the rest of the deck.
The first are split cards. Fire and Ice, for example, are individually useful cards which can be played for two mana. However, when Fire // Ice is in your hand or library, its mana value is equal to that of its two halves added together. Thus, it won’t mess up your cascades.
The second are Adventure creatures. Bonecrusher Giant and Brazen Borrower both have mana value of three, and yet they have adventure abilities that provide cheap interaction to help you get to turn three on level pegging. They’re also nice two-for-one spells to play when the game goes longer.
Next – and most important in the current era of Modern – are the pitch spells. The Forces and the Pitch Elementals have high price tags to hardcast them, but they can all be cast for free, and at instant speed, by exiling a card from your hand. Since the goal is to have a big flurry of action around turns three and four, having access to these cards at key moments gives you a big advantage.
Finally, you can simply play all of the best cards which cost three, four and five mana! These give you an effective backup plan, and can punish people who put too much effort into stopping your cascade game plan.