Card Sleeve Finder
Mayday Games has made a Card Sleeve Finder - available as a browser app or spreadsheet - to help you find the right size card sleeve for your game's cards. It even tells you how many cards each game has.
Mayday updates their Card Sleeve Finder frequently. It covers over 4,000 games! Works on iOS, Android and PCs. The App loads right in your web browser, so just bookmark it.