Great Commander is a boss fought on Venom in Star Fox, composite of three flying parts. The first time it's fought, in Stage 6, its parts combine into a big ship, however the second time, in Stage 7, these combine to create a robot that could easly be inspired on R.O.B.
Star Fox 64
April 27, 1997
Spyborg, known in Japan as HVC-09, is an unfinished robot that serves as a boss for Sector X in the game. It's look is similar to the upper part of R.O.B. and its Japanese name is actually a reference to the serial codes for Famicom accessories (Such as the console itself being HVC-001, the "Zapper" gun being HVC-005, etc. Complete list here). It must be noted that "HVC-009" is not used for any Nintendo accessory, while R.O.B.'s code is "HVC-012".
The robotic operator of the Great Fox, is renamed ROB 64 in the American and European versions of the game, a likely reference to R.O.B. since also its original Japanese name featured a Nintendo reference, being "NUS 64": while 64 is an obviuos reference to the Nintendo 64 console, NUS stands for "Nintendo Ultra Sixtyfour", that's the Nintendo 64 project name, and NUS is actually used followed by a number as serial codes for the console and its accessories (Such as the console itself being NUS-001, the controller being NUS-005, etc. Complete list here). Like with Spyborg, there's no accessory using the NUS-064 code.
ROB 64's look, however, has nothing to do with R.O.B., apart from being a robot.
WarioWare: Smooth Moves
December 02, 2006
While this link happens in a Wario game, since Nintendo holds the rights for all three series, the Star Fox microgame is an actual version of Star Fox, and featuring R.O.B. creates an in-universe link between Star Fox and the Robot series. In conclusion, even if this happens within WarioWare: Smooth Moves, R.O.B. has at all effects appeared in the Star Fox universe.
Copyrights for both series are held by Nintendo.