Now that I have created a bunch of decks for the Call of Cthulhu card game, I thought it would be a good idea to protect them in card sleeves.
I bought a bunch of Cthulhu art sleeves a while back. These were done by Fantasy Flight (same as the recent Netrunner sleeves that I double-bought).
Here they are:

I put my MU explorers deck in the ‘summoning’ sleeves. These probably should be used for my Silver Twilight deck.
I only have three sets of art sleeves. For my other decks I had to use plain-coloured ultra-pro sleeves that I reclaimed from some very old Magic The Gathering decks.
They don’t look nearly so good.
Here is my Yog deck in rather-too-bright red sleeves.
The Cthulhu sleeves are all out of print. I think the best move is to get some more regular ultra-pro plain sleeves but in more subdued or appropriate colours. Purple for Yog. Yellow for Hastur (when their expansion comes out). I could use orange for the MU Explorers (allowing me to reuse the summoning sleeves for Silver Twilight). A dark blue would go well for an Agency deck.
I do have some black sleeves, which I used for the story cards and my old school, black-bordered, collectible-era domain markers.

Black for the story cards and domain markers. The domain markers are the ones that came with the original premium starter sets from the old collectible version of the game.
The domain markers look good in black, but I think brown would be better for the stories. Or maybe gold. I will see what I can find.