Some of the available stitch guides are from SharonG herself. Others are by other stitch writers. Here are links to the canvases with guides I know about, listed by stitch guide writer. To find out if your favorite SharonG canvas has a stitch guide, consult the designer herself. A few guides are listed on her website but many many more are available now.
UPDATE: SharonG is going to be represented by Fleur de Paris starting in the Spring of 2014. Sharon says they are going to bind her guides and use a new numbering system for them to match what they use for all their artists in their catalogue. Once everything is on their website, I will add a link to the SharonG page here.
Maria's Door (from the Positano Landscape Series) -
Dragonfly 6x6-04 (from Insect Triptych, parts of which can be used on the other two canvases)
Horses from the Rear BH 02 (from the Graphic Girls series)
Fish Out of Water
Triplets II "Koi" (from the Triplets Triptych)
Riveria (from the Tuscan Landscape Series)
Terrace (from the Tuscan Landscape Series)
Five Vases with Curly Bamboo
Roulette Wheel Bra and Tap Pants Lingerie Set
10-2-4 Cat and Fish Tripytch (Side Panels Done- Center Panel UNDERWAY)
I believe some of SharonG's ball gown canvases and some of her fountain pen series have stitch guides but I have not been able to find specific information online. Ask SharonG if you are interested.
Here are other authors of guides for SharonG canvases (besides Sharon herself).
The Vintage Geometric Series
Red Ribbon with Hearts Rectangle - I understand this is no longer available (February 2019).
Lavender Fields (from the Tuscan Landscape Series) - This was a cyber class that is retired but you may still be able to buy class instructions. Contact Carole Lake for more information at second link below.