Yes, you can transfer as many Pokemon as you like from Pokemon Ranger, however you must reset your save file and "capture" these Pokemon again in the new save file.
In the original Pokemon Ranger, you can transfer a single Manaphy egg per save file to any Gen 4 game via Mystery Gift. If you reset your Pokemon Ranger save file, you can access this event infinite times.
In Pokemon Ranger: Shadows of Almia, you could transfer a Manaphy, a Darkrai, and a Riolu. However, in this game you needed to download the missions to access this Pokemon from Nintendo Wi-fi Connections during specific periods of time. They were essentially limited time events that can no longer be accessed.
In Pokemon Ranger: Guardian Signs, you can transfer a Deoxys, Heatran, a Manaphy Egg, and a Shaymin to any Gen IV game, like you could transfer in the original Pokemon Ranger. Deoxys specifically is quite difficult to obtain in these times, as you would need to do the mission to obtain it in multiplayer mode. Two people need to press two different switches at the same time, therefore making it impossible to complete single player. Depending on how the encounter goes, it could be caught in any of its 4 forms. However, this Deoxys can be encountered and transferred infinite times per save file, but each core Gen IV game can only receive each Deoxys form once.
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Hope I helped, sorry this question took 11 years to answer
