Throughout all these years many different models of the Joy-Con have been manufactured with different housings, but the shape of all of them has always been the same. That could change in the future if we consider a patent registered by Nintendo that shows the design of a Joy-Con that is individual.
The VGC portal is the one that has echoed this patent that was actually filed by the big N in May 2018 and it wasn’t until April of this year that it was officially registered. From the shape of the images you have accompanying the news, it seems that these are controls that could not be fitted into the console, as is the case with normal Joy-Con, as these new ones look like they would do without connectors on the sides.
According to VGC, this type of independent Joy-Con could actually be an ideal complement for all those who have a Nintendo Switch Lite, because this model of Nintendo Switch requires the use of additional Joy-Con for all those who want to enjoy some kind of multiplayer. A disadvantage that does not occur with the basic switch because two players can be joined using a single Joy-Con each.
In fact, for the upcoming Super Mario Galaxy to be included in Super Mario 3D All-Stars, an additional Joy-Con will be required for the multiplayer, since the second player will have to make use of the motion sensor of the controller pointing at the screen. This of course would be a good example to use this type of new Joy-Con or any other. Of course this doesn’t have to mean that Nintendo is making these individual Joy-Cons. It may simply be a prototype you have in mind, but how it ends up seeing the light is another story. That doesn’t mean that it wouldn’t be a good product to have in mind, so time will tell what it all ends up with.