Taken from Tober's Steam guide.
If you venture into the ember veins, you will encounter Essence Drinkers, Essence Gorgers, and the like. These ashen grublike creatures can drop adornments, which are a sort of mystical addition to your regular gear, and which grant additional stats while you are inside an ember vein. Group side adornments are Mythical (violet) tier, while solo side adornments are Superior (cyan) tier. The adornments comprise two sets, which grant additional bonuses the more pieces you have. Note that both Mythical and Superior adornments count toward each set bonus.
In an ember vein's group loop, you will find a side room containing a well of ember essence in the floor, at which a large number of ashen creatures gather. Among them will be an *Essence Drinker or an Essence Gorger. *Essence Drinkers have a small chance of dropping a Mythical adornment, while Essence Gorgers are guaranteed to drop one. Gorgers are strong (4 chevrons), and summon adds to help them. Be sure to kill any Essence Bursters that appear right away! They will explode if you don't.
It's a good idea to bring some ember resist gear and potions when you go to hunt for your Superior adorments. Also, by the way, an essence well is a great place to fill your ember stone and to level up your alchemy.
In the solo loops, you will occasionally run into a small wandering Essence Drinker, which might drop a Superior tier (cyan) adornment. These have about half the stats of the Mythical adornments.
Some adornments come in three varieties, originally intended for strikers, defenders, and supporters (for group loop adornments, Essence Challengers, Guardians, and Wielders, respectively, and for solo loop, Essence Fighters, Protectors, and Workers). The devs removed the role restrictions shortly after introducing them, but kept the variety, so you have some choice in how you build your character. A few of the adornments only come in one variety and are called Essence Soaked or Essence Dipped.
This guide contains screenshots of the group and solo side adornments I have come upon, or that have been shared with me. Thanks to Andross, Feedpan, Genrah, Jericco, Kisulae, Littlezoe, Mandingo, Raxtin, Roscoejr, Zoonzerker, and (Anonymous) for sharing their adornments info. Special thanks to Kiriko for much updated info.
Summary List of Stats (Group Loop Adornments)
A quick list of what stats you'll find on each item, with set bonuses at the end. Solo loop adornments have values about half these.
Note that there are no adornments yet for Pauldrons or Greaves, as new ember veins are expected to be added to the game.
Level 5 · Pants · Newhaven Valley · Crawling Burrows (Ants)
- Essence Challenger Pants: +19 Hit
- Essence Guardian Pants: +11 Health Regen, +13 Hit
- Essence Wielder Pants: +3 Stamina Regen, +13 Hit
Level 10 · Shirt · Northreach · Torchbug Tunnels (Emberflies)
- Essence Soaked Shirt: +3 Avoid
Level 10 · Gloves · Northreach · Watchers Folly (Bats)
- Essence Soaked Gloves: +8 Haste
Level 10 · Boots · Meadowlands · Noxious Bog (Frogs)
- Essence Challenger Boots: +4 1H/2H/Ranged Damage
- Essence Guardian Boots: +6 Chemical Damage Resists
- Essence Wielder Boots: +6 Chemical Damage Resists
Level 15 · Belt · Meadowlands · Derelict Sanctuary (Mires)
- Essence Challenger Belt: +4 1H/2H/Ranged Damage
- Essence Guardian Belt: +6 Block
- Essence Wielder Belt: +7 Healing
Level 15 · Helm · Meadowlands · Spinners' Recluse (Spiders)
- Essence Challenger Helm: +13 Penetration
- Essence Guardian Helm: +13 Movement Debuff Resists
- Essence Wielder Helm: +13 Stamina Regen
Level 20 · Vambrace · Dryfoot · Basilisk Run (Basilisks)
- Essence Challenger Vambrace: +10 Haste
- Essence Guardian Vambrace: +12 Stun Resists
- Essence Wielder Vambrace: +12 Stun Resists
Level 25 · Faulds · Redshore · Flooded Ruins (Mires, Crocodiles, etc.)
- Essence Soaked Faulds: +7 Enber Damage Resists
Level 33 · Cuirass · Grimstone Canyon (Shrieks)
- Essence Challenger Cuirass: +17 Daze Resists
- Essence Guardian Cuirass: +7 Haste, +7 Parry
- Essence Wielder Cuirass: +17 Daze Resists
Level 40 · Ring · Highland Hills · Blight Root Grove (Mandrakes, Mangroves)
- Essence Challenger Ring: +8 1H/2H/Ranged Dmg
- Essence Guardian Ring: +8 1H/2H/Ranged Dmg
- Essence Wielder Ring: +8 Healing, +8 Haste
Level 46 · Earring · Redshore Ridge · Cragscale Caverns (Cragscales, Spiders)
- Essence Challenger Earring: +8 1H/2H/Ranged Dmg, +8 Stun Resists, +8 Daze Resists
- Essence Guardian Earring: +10 Haste, +10 Ember Debuff Resiss
- Essence Wielder Earring: +8 Movement Debuff Resists, +8 Stun Resists, +8 Daze Resists
Level 50 · Necklace · Grimstone Canyon · Arkhos' Lair (Drolscs, Stonecoats)
- Essence Soaked Necklace: +7 Physical/Mental/Chemical/Ember Debuff Resists
Adventurer's Armor Set Bonuses
Helm, Cuirass, Faulds, Vambraces
- 3 Pieces Active: +3 Ember Damage Resists
- 5 Pieces Active: +7 Ember Damage Resists
Adventurer's Attire Set Bonuses
Earrings, Necklace, Rings, Shirt, Pants, Gloves, Boots
- 3 Pieces Active: +15 Hit
- 5 Pieces Active: +17 Hit, +2 Ember Damage Resists
- 10 Pieces Ative: +41 Hit, +6 Ember Damage Resists
5 · Pants · Newhaven Valley · Crawling Burrows (Ants)
  |
  |
  |
10 · Shirt · Northreach · Torchbug Tunnels (Emberflies)
  |
10 · Gloves · Northreach · Watchers Folly (Bats)
 |
10 · Boots · Meadowlands · Noxious Bog (Frogs)
  |
 |
  |
15 · Belt · Meadowlands · Derelict Sanctuary (Mires)
  |
  |
  |
15 · Helm · Meadowlands · Spinners' Recluse (Spiders)
 |
  |
  |
20 · Vambrace · Dryfoot · Basilisk Run (Basilisks)
  |
  |
  |
25 · Faulds · Redshore · Flooded Ruins (Mires, Crocodiles, etc.)
  |
33 · Cuirass · Grimstone Canyon · Shrieking Barrows (Shrieks)
  |
  |
  |
40 · Ring · Highland Hills · Blight Root Grove (Mandrakes, Mangroves)
  |
  |
  |
46 · Earring · Redshore Ridge · Cragscale Caverns (Cragscales, Spiders)
  |
  |
  |
50 · Necklace · Grimstone Canyon · Arkhos' Lair (Drolscs, Stonecoats)
  |