Here we will look at the arsenal of attacks Juvia has and how she uses them against enemies. We will mostly be focusing on attacks that have been named unless I feel an unnamed move is significant. These abilities will also be divided up into two different categories: Attacks & Abilities. Attacks refer to offensive abilities and physical attacks. Abilities refer to something passive or more tactical in nature. Abilities will also refer to things she does outside of battle or to her body. If you want more info on the workings of magic and its origin see here.
Water Slicer (水流斬破 or ウォータースライサー) is the very first attack Juvia is seen using against Gray during the Phantom Lord arc. It has become a staple in her arsenal since and she uses it often. Juvia creates a few small blades of water that she then sends at her attacker. The water is so strong and sharp it can easily cut through people and stone. This ability is also very easy for Juvia to execute, often needing only a wave of the hand.
Water Jigsaw (水流激鋸 or ウォータージグソー) is an attack where she turns part of her body into a cone of Water Slicers. She first used this attack against Gray during the Phantom Lord arc. In one form, she had a swirling cone of water slicers leave her hand to travel at her opponent. While under Vidaldus Taka's control in the Tower of Heaven, she turned her whole body into a huge cyclone of Water Slicers, going after Lucy with it.
Water Cane (水流烈鞭 or ウォーターカーネ) is an attack where Juvia hand turns to water and from it, extends a whip made of water. She then lashes it at her opponent to cause damage. This was first seen as just a beam of water against Gray and later when Juvia was under Vidaldus Taka's control, it took on more whip-like qualities when she used it against Lucy.
Water Nebula (水流昇霞 or ウォーターネブラ) is an attack where Juvia creates two waves of fast moving water towards her opponent. As it travels the two waves form a helix-shape, slamming them with great force. This attack was used against Meredy during the Tenrou Island arc.
Water Cyclone (水流台風 ウォーターサイクロン) is an attack first seen during the Naval Battle in the Grand Magic Games. Juvia holds her two hands out in front of her and torrent starts to form from them. Juvia can then easily aim it at an opponent. This attack is considered rather strong, rivaling Aquarius' water power.
Wings of Love (愛の翼) is an attack Juvia used in the Naval Battle during the Grand Magic Games. This is the first attack or ability of hers to break the standard naming of water magic and this is likely due to Juvia naming it herself in honor of Gray. This was used after Juvia activated her second origin. Juvia raises her arm in the air and from her hand a huge whirlpool appears, pushing opponents away with great force. Another first is pink hearts appearing in the water.
Hand to Hand Combat is something Juvia and most other Fairy Tail mages are adapt at. While other mages use it more then her, shes not afraid to fight up close in a pinch. This is to cover certain unnamed attacks that are more fighting in nature, but still have water properties attached to them. On a few occasions Juvia is seen punching or kicking opponents with water magic coming off her body. The most well known example is probably her having a globe of water around her fist as she punched Meredy during the Tenrou Island Arc. Juvia has also been known to have a wave of water come off her foot as she landed a kick as well.
Unison Raid (合体魔法 or ユニゾンレイド) is something that can only be executed with another mage that has similar magic/abilities. Its considered very powerful and many mages are unable to perform this feat. Throughout the series, Juvia has done Unison Raid the most, having performed it with Lucy and then Gray on three separate occasions. The first time she combined her water magic with Lucy's celestial key Aquarius to create a huge torrent of water, defeating Vidaldus Taka. In the Daphne arc (filler), Juvia combined powers with Gray to create huge icicles to defeat the lizardmen. During the Grand Magic games, Juvia would combine powers again with Gray to defeat Lyon & Chelia and later against the dragons.
Water Body is something thats for the most part unnamed but is a huge part of what makes Juvia's magic amazing. Without even speaking a word, Juvia's body can easily take on the properties of water. Her body doesn't even have to physically resemble the properties of water for it to be in effect. This grants her many new abilities, such as breathing underwater, letting attacks pass right through her and even keeping things/people hidden inside her. More recently in the series, Juvia has even used her Water Body to enter an enemy and then rip him apart from the inside! With her water body, she can also change the properties of water based on her emotions. Sierra (シエラァ) is a form of her water body where she turns scalding hot, like boiling water. She can then attack her target or use it to move more quickly.
Water Lock (水流拘束 or ウォーターロック) is an ability that has multiple uses. Juvia used it during the Tower of Heaven arc to let her teammates breathe underwater and later to keep them safe on the ocean's surface. Juvia can also use this dome of water against opponents. She used it to trap and knock out Lucy during the Phantom Lord arc. In the same arc, she also tries to make Gray drown by trapping him in a Water Lock. The size and properties of the lock depend heavily on what situation Juvia is in.
Conjuring Rain is an unnamed ability in the series and its rather passive. As a child mage she had little control over her abilities; her power would manifest itself as rainfall. Its an ability she probably would of had more control over as she got older if she hadn't been teased for it. As seen with Juvia and other mages, emotions greatly effect ones magic abilities. Being teased and feeling resented lent itself to it sticking around longer then it probably would. When she was defeated by Gray the rain stopped, it has not been seen much since then. However she did cause rainfall on Tenrou Island when she became angry at Meredy.