In Memories of Ice it is said by a very powerful character that the creator of the Deck of Dragons is long dead. Who created the Deck of Dragons? The Malazan Wikia doesn't address this fact.
From the Complete Malazan Book of the Fallen:
"The Deck of Dragons. A kind of structure, imposed on power itself. Who created it? No-one knows. My belief – Tattersail’s belief – is that each card is a gate into a warren, and there were once many more cards than there are now. There may have been other Decks – there may well be other Decks . . .I said no-one knows who created the Deck of Dragons. Yet there is another entity equally mysterious, also a kind of structure, focused upon power itself. Think of the terminology used with the Deck of Dragons. Houses . . . Houses of Dark, of Light, of Life and Death . . .Think of the word “Finnest”. Its meaning, as the T’lan Imass know it, is “Hold of Ice”. Long ago, among the Elder races, a Hold was synonymous with a House in its meaning and common usage, and indeed, synonymous with Warren...Where resides a Jaghut’s wellspring of power?"
So Silverfox at least believes that no one knows who created the Deck. Certainly the Deck itself is nothing fundamental, since there are equivalent systems corresponding to older magic: i.e. Tiles and Holds. In other words, the Deck did not come before the Holds (I think). I'm not sure there's any explicit statement elsewhere in the series of who made the Deck.
However, I think there may be a clue in precisely what is said of the Deck's maker.
According to the Crippled God in Memories of Ice:
"It was ever thus. You speak of the Deck as an entity, but its maker is dust, as we both know."
Earlier, of the Warren of Tellann:
What then, is the Warren of Tellann that the T'lan Imass now use? Ah, that warren must have been born from the Ritual itself, a physical manifestation of their Vow of Immortality, perhaps. Aspected, not of life, nor even death. Aspected… of dust.
This could perhaps be a hint that the maker of the Deck is, or was, T'lan Imass or Imass. This is pretty speculative, however.