Saiya-jin Pride
General/All Around Aura-
Typically white and is the same for just about every species (with a few exceptions). This aura is the only aura used by humans, but for other species it represents that the fighter hasn't transformed or powered up. This aura is usually only seen when a character is flying fast. In the beginning of DBZ and all throughout the original DB, this is the only type of aura we see until Vegeta arrives on the planet Earth.
White and Purple Aura-
This was introduced to us by Vegeta during his first fight with Goku. The purple tint in Vegeta's aura defined his evil intentions compared to Goku's pure white Aura. The level of purple in his aura varied, depending on what he was doing. While powering up, the purple simply flowed through the white aura but didn't replace it. However, when Vegeta was powering up his Garlic Gun, the purple in his aura completely took control of his regular aura and became very thick. This signified that Vegeta was powering up a very powerful attack, and the attack turned out to be purple as well. We later find out that Captain Ginyu also had this purple/white aura which was identical to Vegeta's.
Pink Aura-
This appeared in movie 12 after Janemba made his transformation. At first, Janemba didn't have any aura. When Goku and Vegeta fused, he powered up big time and all of a sudden he had this pink aura surrounding him. The aura range was wide and fast flowing, meaning that Janemba was probably getting ready to attack. However, he was still not match for Gogeta and was easily torn up.
Special Auras
Kaio-Ken Aura-
This is red in appearance and dominates over another power-up or transformation aura used at the same time. The overflow of ki is tremendous, and therefore the aura is always thick and powerful. It moves at a more rapid pace everytime the person goes into a new level of the technique (eg. kaioken x2, x3, etc.) We were first introduced to this aura during the Saiya-jin Saga when Goku came back to earth to fight Vegeta.
Mystic Aura-
This is very similar to the standard white aura, with a few exceptions. Instead of a constant flowing, the mystic aura is blocky and sporatic, meaning that sometimes it will appear thick and sometimes it won't. The range of this aura's width is also much wider than the standard. The overflow is immense during the actual mystic powerup, but after that the fighter's aura usually dissapears. During the fight with Majin Buu, we only see this aura a few times right before Gohan was about to fly or moving rubble off himself.
Gregory's Aura-
This was blue in color and very thick. It formed a small tightly packed ball of light around him. When he moved, this aura left a trail of light that dissipated slowly. When Gregory used this aura it signified that he was powered up and moving very fast. Part of Goku's Kaio-Sama training was to smash Gregory with a hammer, but when Gregory powered up with this aura, it was extremely difficult to catch him. Eventually, Goku did it.
Cell's Dead Soul Aura-
This had a yellow color to it and was formed by all the people that cell had absorbed into himself. When he first powered up after landing on the island where Piccolo and Android 17 were fighting on, you could actually see all the dead faces in his aura (like in the image on the left). After this first power-up, his aura still had the yellow color to it but you could no longer see all the faces. A lot of people think that Cell was a super saiya-jin because of his golden aura, but this could also explain it. Noone except for Toriyama knows for sure though.
Kanassa-jin Transcendental Aura
This appeared during the Bardock special after Toma fired an energy attack at the last remaining Kanassa-jin. The Kanassa-jin transformed the blast into 'good energy' that he absorbed into his body. As a result, he transcended into a new form. The new form's aura was pure white with blue tints throughout it. The ki overflow was slow but very thick. After the Kanassa-jin did this, Bardock got angered even more and fired a huge blast that destroyed the Kanassa-jin.
Super Saiyjin Aura Variations
Relaxed Super Saiya-jin Aura-
This was not very brilliant or strong. This signifies that even though the Saiya-jin is in an extremely powerful state and the ki energy is overflowing, they are attempting to keep it under control. After some training or several uses of the transformation, a Saiya-jin can even keep the aura from coming out at all while relaxed. This shows a complete mastery of the form and is known as Super Saiya-jin Full Power.
Preparing/Powering Super Saiya-jin Aura-
This is much more brilliant than the relaxed Super Saiya-jin Aura. The overflow of ki grows rapidly because the Saiya-jin is building power to either attack or excel to a new level. The new level does not necessarily have to be Super Saiya-jin 2, but through just the regular Super Saiya-jin form an experienced fighter has different levels of power. The width of the aura is much wider than the relaxed aura, and it flows more smoothly and all in one direction. This signifies that the fighter is concentrating on building the power.
Super Saiya-jin Attack Aura-
This takes on a whole new level of Super Saiya-jin Aura. The aura becomes thick in most instances and more brilliant than even the Powering up Aura. When the Super Saiya-jin is attacking, it isn't worth it to try to control the aura so it basically goes berserk. The rapidness of the flow increases, as well as the width and height of the overflow range.
Super Saiya-jin 2 Aura-
This is similar to the regular Super Saiya-jin Aura, but was a little more brilliant and wider. The flowing of this aura is also slightly more rapid. The main difference that seperates this aura from the regular aura is the electricity. After transforming into Super Saiya-jin 2, the fighter has electric currents flowing through him and his aura.
Brolly's Green Aura-
This was identical to the regular Super Saiya-jin Aura, except that it had a greenish tint to it. This was supposed to represent that Brolly was the Legendary Super Saiya-jin. Aside from the obvious color change, the aura didn't have much else difference between the regular Super Saiya-jin Aura.
Super Saiya-jin Genki Dama Aura-
This was so bright and brilliant that you could barely see Goku when right next to him. During movie 7, Goku powered up a huge Genki Dama and then unconsciously absorbed it into himself. The width of the aura (at a guess) was probably 200 yards (about as wide as two football fields). The aura wasn't very thick though, because he moved right next to Super Android 13 and took him out with a few punches. After it was all said and done, Goku couldn't even remember what happened.
Super Kaio-Ken Aura-
This is a combination of the Kaio-Ken technique and Super Saiya-jin. This was showed to us during the Anoyaichi Budoukai (Afterlife Tournament) while Goku was fighting Paikuhan. Goku transformed into Super Saiya-jin and then used the Kaio-Ken to increase his speed and power. As stated earlier, the Kaio-Ken aura overwrites any other aura, so after a few instances of golden aura flowing through the red of the Kaio-Ken, it just turned into thicker red aura.
Techniques Involving Auras
Aura Barrier-
This appears several times during different episodes and movies. The fighter basically transforms his aura into a hard shell of ki that keeps out energy attacks to a certain extent. This was first revealed to us during the third Dragonball Z movie by Goku (as shown in the picture to the left). Another instance of this was during the Trunks TV Special and used by Gohan. A third and different variation of this technique was used by Vegetto during the Buu Saga. This variation, however, hugged the body of the fighter instead of forming a shell around him. Overall, this technique was extremely helpful.
Pushing Aura-
This was a technique used to knock an opponent off guard. The fighter would make the flow of aura incredibly rapid which would create an outward flow, basically pushing the opponent backwards. A reverse of this technique could be used by extremely experienced user that could stop the person in mid-air if they were moving uncontrollably. This technique was used by Goku and Furiza several times during the Furiza saga. It also appeared several more times through the rest of the series.