I am currently using Fantasy Flight Sleeves, I also use these for my foils along with perfect fits because i like the feel and thickness of them https://www.amazon.com/Clear-Sleeves-Standard-Card-Game/dp/1589945158/ref=sr_1_2?ie=UTF8&qid=1518103332&sr=8-2&keywords=fantasy+flight+sleeves
Amazon isn't the place to get sleeves. They're about twice as expensive as other online retailers.
Also a rule of thumb: If the sleeves come 100 in a pack or don't say "premium" on the package, they're unsuitable for board/card games.These are what are referred to as "penny sleeves".
edit: Since some people want to downvote this comment, let me show you something. Here's a few examples of some commonly used sleeves from two of the most popular brands.
A pack of Fantasy Flight standard sleeves for $5.38. The MSRP on this is $2.99. They're available for around $2.50 at a lot of online retailers.
FF mini euro sleeves. Sold on Amazon for $4.42. The MSRP on these is $2.49.
Mayday Standard USA. $6.13 on Amazon. They retail for $2.99 for a pack of 50.