You make the card 4

[Birdbrain]

I voted creature, and am hoping a {G} creature gets created

[All-Mana Mania]

1 red/blue 3 generic

Double strike, haste, hexproof

Whenever ? Deals combat damage to a player you may cast an instant or sorcery card from a graveyard. Exile it at the end of turn.

Whenever ? Dies return all exiled cards to their owners hands.

3/4

[Birdbrain]

1 red/blue 1 generic

Double strike, haste, hexproof

Whenever ? Deals combat damage to a player you may cast an instant or sorcery card from your graveyard.

3/4

wow! What happens to the card after its cast a second time? I'd definitely use this as is

[Baneslayer]

Enchantment

[All-Mana Mania]

1 red/blue 1 generic

Double strike, haste, hexproof

Whenever ? Deals combat damage to a player you may cast an instant or sorcery card from your graveyard.

3/4

wow! What happens to the card after its cast a second time? I'd definitely use this as is

Probably exiled

[Silent1236]

1 red/blue 1 generic

Double strike, haste, hexproof

Whenever ? Deals combat damage to a player you may cast an instant or sorcery card from your graveyard.

3/4

Woah.  That's pretty broken. 2 mana for a 3/4 is good to begin with.

I'd play it 

[All-Mana Mania]

And the flavor text "oh lookie here, more experiments to do!"

[All-Mana Mania]

Just updated the card

[InfinitiveDivinity]

1 red/blue 2 generic

Double strike, haste, hexproof

Whenever ? Deals combat damage to a player you may cast an instant or sorcery card from a graveyard. Exile it at the end of turn.

Whenever ? Dies return apl exiled permanents to their owners hands

3/4

The only problem is that Instants and Sorceries aren't Permanents. If you're trying to have the user get back their exiled spells that he exiled, I would word it like this: "When ? dies, return all cards exiled by ? to their owners hands." This also prevents him from being absurdly broken by being able to bring back {Sever the Bloodline}d/{Oblivion Ring}ed/etc. cards. If he sends back all of the exiled cards he's just too strong. Balance 😉

[Frothandslosh]

Maybe we'll finally get some sort of "{T}, pay whatever mana, draw a card" land.

[Wackaman9001]

Went with instant/sorcery, but my heart wasn't in it.

Ideally I would create a powerful aura that has a built-in protection from getting 2-for-1'ed. {Rancor} is very lonely in that department, and is a green 1-drop. If I had my way, I'd make a white or white/blue 3-4 drop aura that includes a rancor-ish effect.

{Angelic Destiny}?

This^^ is why I voted enchantment, but I wouldn't be upset over artifact either. So what rarity will it end up? Most likely mythic, sadly

[Gorzo]

Totally forgot about angelic destiny Still, more playable auras would be nice. But I'd really like too see what kind of instants/Sorceries the player-world can come up with - I love {Vanish Into Memory} which came out of the last "you make the card."

[Wackaman9001]

Where is {vanish in to memory} useful? I think it can be used for getting a few extra cards, but you also have to throw them away when it comes back.

[Gorzo]

Where is {vanish in to memory} useful? I think it can be used for getting a few extra cards, but you also have to throw them away when it comes back.

Use it after a pump spell like {giant growth}, or targeting a massively top-heavy creature like {Ball Lightning}, or targeting a token that will never come back at all... It can be used in many ways, and at the very worst, it functions as a "draw X cards, discard X cards, plus flicker a creature" which is incredibly useful.

[Birdbrain]

Or with a creature with high power and low toughness. There are some 5/1's that woul be perfect targets