The Tailed Beast Plan is Kabuto's plan to synchronize Sasuke Uchiha, Kalaile Sarutobi Yuhi, and Misako Terumi with Biju he created to make them into pseudo-jinchuriki. He aims to use them as weapons of destruction and sell them to organizations such as the Akatsuki and nations at the brink of war.
He only made four successful living Biju, though he considers one a failure. Kabuto aims to combine the Biju to create an even stronger being than all of the nine Biju combined. He then wants to transfer Orochimaru's soul into the creature which he believes will create a monster that only he can control and use.
The One-Tailed Cat was a Biju created by Kabuto. This is the first experimental Biju that successfully survived yet was named a failure as it was the size of an average housecat. It was accidently found by Ino and not knowing what it was, she kept it as a pet which she named Toruka.
The Two-Tailed Fox was the second Biju that was successfully created by Kabuto by fusing the little amount of the Nine-Tailed Fox and Two-Tailed Monster Cat's chakra he had collected. This was the first one he considered a success. This is the Biju Kabuto planned on sealing into Kalaile.
The Five-Tailed Wolf was another Biju Kabuto created fusing together many different chakra natures together. Kabuto planned on sealing this beast into Sasuke, after recapturing him.
The Six-Tailed Weasel was the last Biju Kabuto was able to create. He planned on sealing this into the Fifth Mizukage's daughter Misako Terumi.