While Dragon Shield Sealable Inner Sleeves advertise that they fit 2.5'' x 3.5'', standard size cards, they do not. They are very tight (tight enough to potentially cause damage) and about half a millimeter too short. You can see the flaps fold edge on the face of the card which makes the tops of the cards thicker than the bottom which is not ideal if you want your cards to be flat.
Probably better for Magic the Gathering from what I've looked up, but that's about it.