A blocker that can dig deeper into your deck and find you pieces is a must-have
It can also be worth splashing black for cards like Smiting Helix, Etchings of the Chosen and even more changelings
This pinpoint nature is why these kinds of cards typically tend to be incredible sideboard cards, coming in against the decks they're best against while not being in your hand against decks that don't have a strategy heavily focused on a specific card
Escape Tunnel is also a heavily-played card in the format's Landfall decks, but it will likely be swiftly replaced with Evolving Wilds
A near mint condition (NM 7) copy of the card could still net you a cool a 5,850 if you happen to have one collecting dust in your cupboard
Other mayhem cards need flash enablers to allow you to cast them at instant speed, or you can use Green Goblin (the backside of Norman Osborn), to give mayhem to every card in your graveyard, including other instants or flash creatures