If we think of each block as either new territory or a revisit, we have: Mirrodin [Revisit of Antiquities], Kamigawa [New], Ravnica [Revisit of Invasion] Time Spiral [Revisit of Everything], Lorwyn [New], Shadowmoor [New] Shards of Alara [New], Zendikar [New], Scars of Mirrodin [Revisit of Mirrodin] Innistrad [New], Return to Ravnica [Revisit of Ravnica], Theros [New] Khans of Tarkir [New], Battle for Zendikar [Revisit of Zendikar], Shadows over Innistrad [Revisit of Innistrad] Revisit-New-Revisit-Revisit-New-New-New-New Revisit-New-Revisit-New-New Revisit-Revisit Time for more New then
The cheaty fat man decks can avoid this issue but it isn't super easy
Most card-draw spells net you 1 extra card for 3 or 4 mana
However, this randomness occasionally finds its way into the attacks of some Pokmon, and Alolan Exeggutor ex's attack has a chance to be amazing or horrible depending on what happens with a coin flip