Eldritch Horror is my fave game and as I play it a fair bit I have lovingly sleeved all the cards. Needless to say this has made some of the decks impossible to handle for the purposes of shuffling efficiently, searching and stacking on the game table (Looking at you Assets, Spells, Conditions and unique Assets decks!)
To make the decks mentioned above more manageable I have some personal house rules regarding deck setup that I would like to share and hopefully help some fellow EH fans out.
Asset Deck: This deck sleeved is absolutely monstrous and impossible to stack all together in nice shiny FFG sleeves. After shuffling I cut the deck into 4 roughly equal sized decks and place each one under one of the 4 blank reserve spaces during setup. Each "mini" deck then becomes the feed for that particular reserve space above it when one of the assets are acquired by an Investigator. If I have to search the Asset deck during play I roll a d4 and then search that "mini" Deck for whatever I am looking for. Of course after searching I would reshuffle that particular "mini" deck. If a deck runs out of cards I just form a new "mini" deck by taking a bunch of cards from the other active decks.
Spells: I shuffle the cards into 2 separate decks. Whenever I need a spell I roll a dice (1-3 I use deck one, 4-6 Deck two)
Conditions: No need to put all of the conditions into one deck that I know of, even without sleeves. I sort the conditions into 5 decks comprised of the following:
Deal Deck:- (Debt, Funding, Dark Pact and Agreement)
Divine Deck:- (Blessed, Cursed and Righteous)
Hindrance Deck:- (Detained, Lost in Time and Space and Hunted)
Madness deck:- (Amnesia, Hallucinations, Hunger and Paranoia)
Hurt Deck:- (all Injuries, Hypothermia, Poisoned and Infection)
Unique Assets: I separate the cards into 3 decks (Task, Ally and Item)
Hope this proves helpful.