Ah, Wrath effects, the bane of creature decks everywhere. Named for the great granddaddy of them all, Wrath of God, they can eliminate all your hard work in an instant. But there are a few ways to work around them.
If playing a deck likely to have a wrath, don't play all your creatures. Keep one or two powerful creatures back in your hand to play once the creatures on your board get wiped. It will slow down your ability to crush your opponent, but you won't be left completely high and dry if they kill your existing board.
Protect your creatures
Selfless Savior can protect one of your creatures from destruction. Linvala, Shield of Sea Gate can protect all of them, as can Heroic Intervention (assuming you kept 2 mana open). Some cards, like Seasoned Hallowblade and Toski, Bearer of Secrets protect themselves. That said, black -X/-X effects and exiling wraths can still kill these.
Use death triggers to get revenge, or refill your board state
Creatures like Beskir Shieldmate or Garrison Cat replace themselves with tokens when they die. Anax, Hardened in the Forge, Basri's Lieutenant, and Hofri Ghostforge can replace your entire board. Luminous Broodmoth brings your creatures back from the grave, and Bastion of Remembrance punishes your opponent for killing them. Exiling wraths dodge death triggers, though.
Use non-creatures that survive wipes to refill your board
Crawling Barrens and Faceless Haven will survive most wipes on account of not being creatures at the time. Castle Ardenvale can refill your board and Castle Locthwain can refill your hand. Vivien, Monsters' Advocate will keep churning out tokens turn after turn, and doesn't die to Wraths.
Use creatures that can come back
Creatures that can return themselves from the graveyard to hand or battlefield can keep you from ever running out of creatures. Exiling wraths dodge this technique as well.