What was first? The art, the effect or the name of a card?

I'm wondering, how the design of an expansion works.

Do they create a theme, which they give to their artists and create the cards afterwards with the obtained art? 

Or do they crate the card and go to the artist like "draw me this"? 

I’d say it’s all of those things. And I’d say the art team has a huge library of unused art just waiting to be thrown on a card.

Look at what’s her name from the Dalaran Heist. The Druid of the swamp art probably existed when KnC was in development

Cards' design come first: effects and interactions define the gameplay so they're the first thing they think about. Then it come graphic: for the most important cards of each set they've got a dedicated team of artist that make it on demand, while for the fillers I think they've got a sort of pool with unused and previously discarded art. Names come as last, but the most iconic cards are probably already named from the beginning since they're themed to the set itself.

Quote From sinti

All of the above. Depends on a card. They said so many times in interviews ;-)

This is correct.

In some cases, they know the character they want to add, but have to figure out what sort of effect it will do or how it will look.  The Death Knights are a good recent example: they knew they wanted all of the classes to be 'death knights' early on but had no clue how that would actually play out.  They were literally weeks from finishing the set before they even figured the answer out.

In other cases, they know of a great mechanic or card they want to add, then have to decide what sort of character will that fit that card.  Reborn, IIRC, has been in mind for a while now without even a set to put it in, nevermind artwork or the character.

Sometimes, the whole card basically plops in their face and it just needs tweaks.  The second they knew Old Gods was going to be the thing C'thun's design basically flew together including how it needs to grow over time and 'loom' over the game and how it should be devastating but not QUITE game ending.  The design was more about tweaking than figuring anything out.

So yeah, there's no direct sequence.  Each card comes to life in different ways.

Quote From sinti

Quote From griffior

And I’d say the art team has a huge library of unused art just waiting to be thrown on a card.

Thats what i do :D I hoard so much art for custom cards, never gonna use all that, but you know ... what if i needed that :)))

Not gonna lie, It's hard to find quality art for custom cards without it feeling reused