At 3rd level, a barbarian gains the Primal Path feature. Here is a playtest option for that feature: the Path of the Wild Soul.

Path of the Wild Soul

The realm of the Feywild abounds with beauty, unpredictable emotion, and rampant magic. A barbarian exposed to this realm feels emotions powerfully and magic saturates their body. When a barbarian who follows this path rages, it is a bellowing roar for freedom, an explosion of expression, manifesting in unpredictable ways.

Path of the Wild Soul Features Barbarian Level Feature 3rd Lingering Magic, Wild Surge 6th Magic Reserves 1d4 10th Arcane Rebuke 14th Chaotic Fury, Magic Reserves 1d6

Lingering Magic At 3rd level, your body reacts to the presence of magic. You can cast the detect magic spell without using a spell slot or components. Constitution is your spellcasting ability for this spell. You faintly glow a color corresponding to the school of magic you detect (you choose the colors). You can use this feature a number of times equal to your Constitution modifier (minimum of once). You regain all expended uses when you finish a long rest.

Wild Surge Starting at 3rd level, magic erupts from you as you rage. When you enter your rage, you must immediately roll on the Wild Surge table to determine the magical effect produced. If the wild surge requires a saving throw, the DC equals 8 + your proficiency bonus + your Constitution modifier. Wild Surge d8 Effect 1 Necrotic energy bursts from you. Each creature within 30 feet of you takes 1d10 necrotic damage, and you gain temporary hit points equal to the sum of the necrotic damage dealt to the creatures. 2 You teleport up to 20 feet to an unoccupied space you can see. Until your rage ends, you can activate this effect again on each of your turns as a bonus action. 3 You conjure 1d4 intangible spirits that look like flumphs that appear next to you. Each spirit immediately flies 30 feet out in a random horizontal direction from you, only stopping early if they come in contact with a crature or object in their path. At the end of your turn, all spirits explode and each creature within 5 feet of one or more of them must succeed on a Dexterity saving throw or take 2d8 force damage. 4 Arcane energy enshrouds you. Until your rage ends, you gain a +2 bonus to AC, and whenever a creature within 10 feet of you hits you with an attack, that creature takes force damage equal to your Constitution modifier. 5 Plant life temporarily grows around you until your rage ends, the ground within 10 feet of you is difficult terrain, and moves with you. Furthermore it does nothing to impede your movement. 6 Arcane energy taps into the minds of those around you. Each creature within 30 feet of you must succeed on a Wisdom saving throw or you see a glimpse of the creature’s thoughts, learning how it plans to attack you. As a result, the creature has disadvantage on attack rolls against you until the start of your next turn. 7 Shadows weave around a weapon of your choice you are holding. Until your rage ends, your weapon deals psychic damage instead of its bludgeoning, slashing, or piercing damage, and it gains the light and thrown properties with a normal range of 20 feet and a long range of 60 feet. If you drop the weapon or throw it, the weapon dissipates and reappears in your hand at the end of your turn. 8 A beam of brilliant light lances from your chest in a 5-foot-wide, 60-foot-long line. Each creature in the line must succeed on a Constitution saving throw or take 2d8 radiant damage and be blinded until the start of your next turn. You have enough time to aim this beam, but you can not reposition yourself.

Magic Reserves At 6th level, you can channel the magic surging inside you into other creatures. As an action, you can touch a creature and roll a d4. The creature recovers an expended spell slot of a level equal to the number rolled. If the creature you touch can’t recover a spell slot of that level, the creature instead gains temporary hit points equal to five times the number rolled. You can restore a total number of spell levels equal to your barbarian level, if the result on the die would exceed the amount of spell levels you have left, it instead restores a spell level equal to the number of spell levels remaining. The total number of spell levels you can restore resets on a long rest. When you reach 14th level in this class, you increase the die to a d6.

Arcane Rebuke At 10th level, the magic crackling within your soul lashes out. When a creature forces you to make a saving throw while you are raging, you can use your reaction after you roll the saving throw to deal 3d6 force damage to that creature so long as you can see them.