Here you can find a wonderful selection of indie-made Father's Day cards. 

Red Cap Cards is a celebration of art and correspondence. Each illustrator is hand-selected for their stunning work, individual point-of-view and notable achievements in children’s book illustration, animation, design, and modern art. Red Cap Cards is a platform for artists to reach a broad audience, bringing together the artist’s work and the importance of a handwritten letter.
Cards measure 4.25" x 5.25"
-Camping Dad
-So Glad Dad Neon
-Grandpa's Umbrella
-Fishing Dad
-Wombat Dad

Offensive Delightful is a rad, woman-owned company out of LA. The owner, Olga Krigman, is a NYC expat who studied design at the School of Visual Arts. She loves the funny, the vintage, the cool, the sexy. She likes sarcasm and bright visuals. Olga designs and makes everything in Sunny Los Angeles. 
Cards measure 4.25" x 5.5"
-Coolest Dad
-Best Dad!
-Dad Superhero
-Mom is the best Dad
-Midcentury Dad

About the Artist
Yuko grew up in Himeji, Japan surrounded by rice paddies and mountains. She moved to Seattle in '96 for college and worked for a non-profit domestic violence organization for 14 years before taking a leap of faith and growing her business in 2015. She now makes art full-time. She enjoyed making happy art with watercolor, ink, and digital mediums. After living in Seattle for 25 years, she now lives on a 240 acre farm in Arlington, Washington as part of Rooted NW co-housing.
Cards measure 5.5" x 4.25"
-I'm Sorry Father's Day is Tough

Power and Light Press is a ship-shape print shop founded by Kyle Durie and fueled by a fleet of all-female letterpress printers with clean hands and filthy mouths. Since 2009, their cards and gifts have been hand-built to handle all of life’s messy emotions.
Cards measure 4.25" x 5.5"
-Happy Father's Day to You, Mom 

Mazapan Paper Co.
Owned and operated by Pam, the illustrator/creator is a self-proclaimed border-town girl living in Austin, Texas. She designs and packages every single order "con amor" and aims to make illustrated paper goods that are often inspired by her Latine and Texan roots with the goal of spreading love and empowerment. 
Cards measure 4.25" x 5.5" and are blank inside.
-You Fill All the Shoes Flawlessly (Happy Father's Day, Mom)

The Curious Culture
Colorful cards for wandering minds. Carlos Carmonamedina is the creative force behind The Culture Curious. As a passionate traveler and artist, he merged his two great loves to bring you a vibrant world of stationery that explores the fascinating intersections of culture, identity, and friendship. To be "culture curious" is to tap into our infinite sense of wonder, where we learn as much about others as ourselves. Stationery is his medium because while it is a small gesture, Carlos believes that the sentiment and energy we put into gifting tangible mementos has the potential to create lasting human connections. Since Carlos began creating cards in 2016, he has discovered that playful themes can uplift hearts and build bridges between distant places. It is this profound appreciation for our shared human experience that drives him to speak to the awe-inspiring multiplicity of this vast planet.
Cards measure 4.25" x 5.5" and are blank inside.
-Love You Dad