1 Baba Uranai
Baba Uranai is an old fortuneteller with connections in the Otherworld (Heaven and Hell). She has regular contact with Enma, King of the Dead. She can also teleport to the Otherworld if need be. In the original Dragonball she gives Goku a chance to speak with his dead grandfather, and in Dragonball Z she teleports Goku back to Earth from Heaven so he can compete in the Ten'kai'chi Bou'dou' kai. Later on she also brings Vegeta back to Earth from Enma's palace so he can aid in the battle against Buu. For those of you who
want a greater understanding of this amazingly minor character, she is also Master Roshi's sister.
2 Tapion and Minoshiya
Tapion and Minoshiya are brothers from the planet Konack who were assigned the imprisonment of the demon Hildegarn. Hildegarn was a creature animated from one of Konack's sacred statues by a group of evil wizards (think Bibidi, Babidi, and Buu). This monster rampaged across Konack destroying cities and murdering the populations until Tapion and his little brother Minoshiya were given magical flutes (ocarinas) in order to calm the demon so that Tapion could use his holy sword to cut it in half. After this, the lower half of Hildegarn was placed within Minoshiya and the upper half within Tapion. If the halves tried to escape they could be calmed once again by the ocarinas. The two brothers were imprisoned within two oracle boxes and send into deep space far away from each other. One of the surviving wizards freed Minoshiya and killed him, enslaving the bottom half of Hildegarn. Tapion's oracle made its way to Earth however. (For more input on this section, I suggest you watch Movie 13, as I do not wish to spoil one of the finest stories in Dragonball movies). Later on, Tapion gives his sword to young Trunks, and then flies away in an exact duplicate of the time machine Mirai Trunks used earlier in the series. It is supposed Tapion found his way home, to a place he could find peace with
the Hildegarn situation well in hand, but he is never heard from again.
3 Janenba
Janenba was the result of all the stored up evil of millions of souls possessing one body. He was around the same strength as Kid Buu. His appearance causes the imprisonment of Enma and the release of all souls in Hell. To defeat this awesome foe, Goku and Vegeta become Gogeta with the fusion technique. (I will not say more, Movie 12 is where this happens, go watch it, it's the best Dragonball movie that was ever made).