Ok so I'm obviously no artist.
That being said, I have adapted this style of auction house from an online text-based RPG. I think it is clean cut and simple to navigate and use. It wouldn't take much work from a proper graphic designer to add a real logo and make it look like it came from Steem Monsters. I am basically making this post as a suggestion for the auction house layout design rather than the graphical design.
A basic run down of features starting from the top:
- There is a "select card for listing" option that would take you to your collection where you would pick a card for auction, the same as if you were sending it to someone. Next to that you would then select duration of auction and decide a starting price (forgot to add a tab for starting price, but imagine it's where the steem monsters logo is).
- Search bar, pretty self explanitory: you can type in the name of a card you want to buy and it will bring up all relevant listings.
- Rarity tabs: In the picture the Legendary tab is open where you can see all the listed legendary cards. You can also navigate across to look at the epic, rare, common, or summoner cards.
- Listings are ordered based on time left in the auction, everyone can see the card, card level, current card owner, current high bidder, number of bids, current bid price, and time left in the auction.
I think a design like this will allow people to easily navigate though the auctions without having to scroll down a number of pages. Really going for a functionality > design with this one lol.
Shout-out to 
Blessed be 
Amen