Envelopes that will fit your 4x6 inch cards like a glove. These A4 envelopes are perfectly sized at 4.25 x 6.25 to hold any 4x6 enclosure.
Premium Vellum Discount 4x6 inch Card Stock for DIY Invitations
Invitation Mat 4 3/4 x 6 3/5 - Cards & Pockets
Joyberg Blank Cards and Envelopes 4x6, 30 Pack White
LUXPaper A4 Invitation Envelopes
Basic Colored 4x6 Folded Card Stock Note Cards
Cards and Pockets - Cut Cardstock
Basic Colored 4x6 Folded Card Stock Note Cards
Environment Nature Inspired Desert Storm Envelopes, When you want a natural but smooth surface for an envelope, the Desert Storm A4 envelopes is a
Environment Desert Storm A4 Envelopes for 4x6 Cards
Classic Linen 4x6 Folded Discount Card Stock Blank 4x6 Linen