These clones were often young clones that are strait from Kamino. Usually, the plain white armor means that they are not part of any particular legion. Although, there are some legions that use plain white armor.
The 212th Attack Battalion was a Battalion of clone troopers that donned white clone armor with orange markings. They were present at the second battle of Geonosis, Umbara, and Utapau. This battalion was led by General Obi Wan Kenobi.
The 501st legion was one of the best in the Grand Army of the Republic. It was lead by General Anakin Skywalker, Comander Ahsoka Tano, and clone Captain Rex. The 501st fought on many battlefronts including Teth, Umbara, and Ringo Vinda.
The 13th Battalion, also known as the "Iron" Battalion, was a battalion in the Grand Army of the Republic that participated in the Clone Wars between the Galactic Republic and the Separatist Alliance. It was commanded by Jedi General Jaro Tapal and a Clone Commander. It fought in the Bracca Invasion, and later participated in the implementation of Order 66 against the Jedi, which resulted in the death of Tapal and the entire unit, as well as the destruction of the Albedo Brave.
This company of clones was a division of the 501st Towards the end of the Clone Wars, they helped the Loyalist Deathwatch Mandalorians during the Siege of Mandalore. Their orange markings of their helmets are representative of their leader Ahsoka Tano.
The Wolfpack wasa special legion of clones who were often sent on delicate operations. They were led by Jedi master Plo Koon and Clone Commander Wolffe. Their numbers were severley devistated at the Battle of Abregado due to General Grevious's new wepon the "Malevolence".
The 327th Star Corps was a unit of clones lead by Jedi General Aayla Secura, and clone Comander Bly. The 327th fought battles on Escander, Quell, Meridun, and Felucia.
The 21st Nova Corp was an elite set of clones under the command of Jedi General Ki Adi Mundi and clone Commander Bacara. Bacara was a ruthless commander. When his troops were outnumberd and out of ammo, he ordered his men to engage the droids in hand to hand combat, eventually winning the day.