There is a Trello board detailing the exact status for designers as well as giving you the option to vote for unsupported designers or suggest new designers.
Below is a quick summary (Updated 2020-01-30)
Well supported (Almost all charts work. But there can still be a few that doesn't)
- Heaven and Earth design
- Artecy
- jan hicks creates!
- Charting Creations
- Paine free crafts
- Tilton crafts
- Pic2Pat
- WinStitch/MacStitch (Using certain export options)
- The Cross Stitch Studio
- Golden Kite
Somewhat supported (Lots of charts work but no promises)
- Long Dog Samplers
- Gecko Rouge
- Cross Stitch Collectibles
- Mystic Stitch
- Fox and Teacup
- Cross Stitch 4 Everyone
- Unconventional X stitch
Can't find what you're looking for?