Dragon's Rage Channeler

Whenever you cast a noncreature spell, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — As long as there are four or more card types among cards in your graveyard, this creature gets +2/+2, has flying, and attacks each combat if able.

Sprite Dragon

Flying, haste
Whenever you cast a noncreature spell, put a +1/+1 counter on this creature.

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Arclight Phoenix

Flying, haste
At the beginning of combat on your turn, if you've cast three or more instant and sorcery spells this turn, return this card from your graveyard to the battlefield.

Detective's Phoenix

Bestow—{R}, Collect evidence 6. (To pay this bestow cost, pay {R} and exile cards with total mana value 6 or greater from your graveyard.)
Flying, haste
Enchanted creature gets +2/+2 and has flying and haste.
You may cast this card from your graveyard using its bestow ability.

Venture Deeper

Target player mills four cards. (Then exile this card. You may cast the creature later from exile.)

Merfolk Secretkeeper

Merfolk Secretkeeper // Venture Deeper

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.