BGG is now carrying the entire Legion Supplies line of card sleeves, made specifically for board games. All sleeves are clear and comes in packs of 50 (except for size #11, which comes in packs of 25).
Not sure what to buy for your favorite game? Please use this BGG Geeklist to look up popular boardgames and it will tell you what size Legion sleeves to buy and how many you need. For example --> Wingspan has 212 cards that are 57x87mm, so you would need 5 packs of #3 sleeves.
#1 = 44mm x 67mm (Mini American) - pack of 50
#2 = 46mm x 72mm (Mini European) - pack of 50
#3 = 59mm x 93mm (Standard American) - pack of 50
#4 = 62mm x 96mm (Standard European) - pack of 50
#5 = 67mm x 92mm (Standard card game) - pack of 50