There were four canceled Star Fox games.

The first, planned for the SNES, was a sequel to the original game and titled "Star Fox 2". It was completed, but its release was shelved in order to continue the series in 3D on the Nintendo 64 with the release of Star Fox 64. Star Fox 2 would eventually see an official release on the Super NES Classic in 2017.

The second was a Virtual Boy release titled "Star Fox" which was canceled due to the poor sales of the console.

The third was a Star Fox game for the Wii, which after years of being talked about ended up being cancelled for unknown reasons.

And the last was an arcade version (also titled "Star Fox"), though very little is actually known about it or why it was canceled. The only known image of this game is shown in the attachment.