Practitioners of Form V included Jedi Masters Aayla Secura, Adi Gallia, Plo Koon and Luke Skywalker, Jedi Knights Anakin Skywalker and Ulic Qel-Droma, and Dark Lord of the Sith Darth Bane.
Practitioners. Kavar, Vrook Lamar, and Zez-Kai Ell, all Form VI instructors. Ironically for a fighting form designed to encourage moderation over aggression, Niman was the chosen discipline of the fallen Jedi-turned-Sith Lord Exar Kun.
Anakin Skywalker was a known user of Djem So, both during his initial stint as a Jedi and later when he subsequently fell to the Sith. The Shien variant of Form V allowed the utilization of an unconventional reverse grip, which Ahsoka Tano was known to prefer and use during battles.
Anakin chose the form because of its aggression, which also fit Vader. The Dark Lord's strength in the Force, along with the physical strength that his cybernetic limbs offered, made the heavy-handed Form V a perfect match. However, there was a subtle difference. Now that Vader was a Sith, he didn't have to hold back.
Practitioners of Form IV included Yoda, Qui-Gon Jinn, Aayla Secura, Ezra Bridger, the Grand Inquisitor, and Anakin Skywalker.
Jedi Battlemaster Cin Drallig and Grand Master Yoda had knowledge and mastery of all seven forms, including Juyo, befitting Drallig's role as lightsaber combat instructor at the Jedi Temple and Yoda's reputation of having mastered all forms of lightsaber combat as did Anoon Bondara, another lightsaber instructor.
Kylo Ren's lightsaber form was something of a hybrid, which blended three styles together: Djem So, Juyo, and Niman.
At first, Rey primarily fights with a lightsaber the same way she would have with her quarterstaff. However, after studying Luke's Jedi scripture and training with Leia, Rey probably uses Form VI: Niman, a jack-of-all-trades lightsaber form that combines different aspects of Forms I through V.
He has used multiple Forms to improve his prowess as a duelist since the start of the Prequel Series. By the time of RotS, Obi-Wan exercised Forms 1, 3, 4, 5 (Shien) & 6 in battle, Soresu and Ataru being his main focus in their stated order.
As with his clone precursors, Starkiller was programmed with the knowledge and skills of his genetic template via memory flashes. As such, he inherited the original Starkiller's preference for the Form V/Shien-style reverse grip, as well as the Form IV/Ataru and Form VI/Niman fighting styles.
There are 7 forms of lightsaber combat, but Soreso, Shein, and Vaapad are the most effective. Soreso, Vaapad, Shein, are the most effective forms because they are all strategic and have their strengths and weaknesses. But the thing they all have in is that you must fully commit to the form.
Practitioners of Form V included Jedi Masters Aayla Secura, Adi Gallia, Plo Koon and Luke Skywalker, Jedi Knights Anakin Skywalker and Ulic Qel-Droma, and Dark Lord of the Sith Darth Bane.
However, Mace Windu—the legendary Jedi Master who popularized purple lightsabers—made modifications to Form VII that aligned it with Jedi philosophy and earned the endorsement of the Council. Windu's Jedi-approved variant of Form VII is known as Vaapad.
Form VII: Juyo (or Vaapad)
Jedi Master Mace windu is the main Jedi known to use this form of combat because Form VII is the most aggressive and only the most Force-sensitive individuals can execute this form successfully. When Master Windu fought Darth Sidious, he used Form VII and took the upper hand in the fight.
Form VII, known by its two primary disciplines of Juyo and Vaapad; and also known as The Ferocity Form, was the seventh form of lightsaber combat. It was considered the most aggressive and unpredictable form.
Form VIII: Kendosu, or the Way of the Varactyl, was a new swordplay style developed during the Great Galactic War by Jedi Knight Scott Borek.
It should be noted that the fourth form of lightsaber combat, Ataru, was also known to employ dual blades as part of its training regimen. Ahsoka Tano was a master in this form when she was only a Padawan, an accomplishment that Jedi Masters would have serious troubles in achieving.
A prime example is Kit Fisto. Kit Fisto was a Skilled Jedi of form I who fought during the clone wars. He almost defeated general Grievous using Form I of lightsaber combats. Other than Fisto, Meera Sutrik, and Obi-Wan Kenobi are the notable names to use Form I of lightsaber combats.
Form II relied on careful and controlled strikes instead of power and strength. Count Dooku was a master of this form and trained the Sith assassin Asajj Ventress in its use, though hers was less elegant than her master's.
Like Anakin, Darth Vader used Form V, also called Djem So, but because his mechanical suit severely limited his physical movements,...
Rey Skywalker
Her Force telekinesis outperformed many Jedi before her. And her power connected with Ben Solo/Kylo Ren to create a legendary Force Dyad. We only saw some of Rey's power, so with her, the sky is the limit.
Darth Revan's Lightsaber Combat Style and Forms
Regarding his different lightsaber forms, Darth Revan presented great acrobatic skill during his fight in the Old Republic game, suggesting that he was a user of the Fourth Form, aka Ataru.
Ezra bridger employed Form IV. This became his primary lightsaber form. Ezra also appears to use form V/Shien and form IV/Ataru mostly for blaster deflection and fighting, respectively.
Form V: Djem So
As stated in numerous sources, Luke takes after his father with his preferred form of lightsaber combat being Djem So.