I love hand-designed stationery. There are many good ones available through Etsy and independently. But my favorite ones thus far include Rifle Paper Co. (which is probably the most popular), Paper Lovely Letterpress, and Quill & Fox.
Rifle Paper Co.
I really like her use of gouache paint, as it creates a nice vintage feel. She sells a variety of paper goods, including cards, journals, calendars, art prints, and custom work.
Paper Lovely Letterpress
I love the understated, friendly feel of this design, and the letterpress adds a nice craftsman touch.
Quill & Fox
Admittedly, this design feels quite similar to Rifle Paper Co., but the artist has a variety of different goods, including cards and art prints.