Legacy: Like Academy and Jar from the same era, High Tide didn't last
The set adds a swathe of instant and sorcery spells with flashback, but also brings in the new Disturb mechanic to allow creatures to return in new forms
In this case, you play lands from the top of your library, and playing spells from here is equivalent to casting them
What were not counting are cards that dig through a certain amount of cards in your library and let you cast a spell, like cascade cards or effects like Sunbird's Invocation
The easiest way is with a Firebrand Archer, a cheap red creature printed in Foundations, which deals one damage to each opponent whenever you cast a noncreature spell
Then each creature your opponents control gets -1/-1 until end of turn for each poison counter its controller has