The Game Boy Wars series

The Game Boy Wars series was started in 1991 with the release of Game Boy Wars developed by Intelligent Systems and published by Nintendo under their Wars series. 3 more games would be released under the Game Boy Wars name, all of which were instead developed by Hudson Soft. The series would end in 2001 with the release of Game Boy Wars 3, releasing less then a month before the first Advance Wars game.

After the release of Game Boy Wars, there would be a 6 year period where no new Wars games would be released; That streak being broken when Hudson Soft released Game Boy Wars Turbo in 1997. They would quickly release the ladder 2 Game Boy Wars games over the span of ~3 years.

There was also 64 Wars planned. It was also developed by Hudson Soft and was supposed to be released for the Nintendo 64. You would be able to connect Game Boy Wars 2 (I presume via the Game Boy link cable) to the game and keep your progress on the go. 64 Wars was slated to release in early 1999, but was delayed to late 1999 and ended up never coming out for unknown reasons.

The games slightly differed in setting compared to the original Famicom Wars -- and subsequent mainline sequel Super Famicom Wars and later Advance Wars series -- with Blue Moon being replaced by White Moon. They would also differ in gameplay compared to their mainline counterparts; One of the most notable ways being that the Game Boy Wars games feature a diagonal grid.