The Lonely Island. He's been mentioned a few times but in the interest of keeping this list complete You must visit Opher at The Lonely Island. There's the possibility of exchanging with
Lost Ark Gold your Island Souls for awesome turtle skins, and much more. You'll also get an unrestricted Island Soul by simply talking to Opher.
Golden Wave Island. It's an island full of loot chests. If you're in the market for lots of stuff (Pirate Coins, card packs green engravings) with very little effort.
Panda Island. Be sure to avoid this island if you like panda's. Other than that, there's an extremely brief blue and purple questline that offers plenty of Silver, Weapon and Armor Crystals, Harmony Shards and Harmony Leap
Turtle Island. Completely completing the quest not only awards you with the Island Soul and valuable Jewel Coral as well as an Turtle mount. It is possible to pick the color.
Serenity Island. In just a few seconds and you'll be rewarded with a beautiful pile of Weapon and Armor Crystals. On top of that you'll earn the Skill Potion through the Stone of Power quest, which requires a rerun of an earlier dungeon, the Morai Ruins and Tortoyk's Heart dungeons.
Peyto, Glacier Island, Lullaby Island, and Dreamgull Island. While technically a boat go to Peyto and do Island quests. Make sure to complete the yellow quest , which provides an emote. Additionally, obtain the Song of Resonance from Treasure Hunter
cheapest Lost Ark Gold (you'll need it for the various islands). After that, head to Glacier Island and continue the quest line. After that, go to Lullaby Island, do the quests again, and obtain forest's Minuet song. The latter can be used to complete Dreamgull Island. It's going to take some time, but you'll end up having four Islands Souls and heaps of upgrade materials.
The Wall