Hi all, here we go! Huge thanks to HungryGoblin for providing the drops info for us.
Velvet Clydesdale: Fertilizer, Horse Hair, Sugar, Carrots
Black Bear: Fur, Rat Tail, Creep Tooth, Jewels, Silver Ore, Prime Cut, Bone, Bacon, Skunkupine (monster), Fangbeast (monster), Fey Crystal (rare)
English Sheepdog: Light Armor, Longsword, Simple Feast, Hearty Feast, Fur, Rat Tail, Creep Tooth, Milk, Fey Crystal (rare)
St. Bernard: Light Armor, Longsword, Simple Feast, Hearty Feast, Fur, Rat Tail, Creep Tooth, Milk, Fey Crystal (rare)
Kitsunecorn Den: Earth Wisp, Wisp Lantern, Elvenite, Expansion Permit
Flower Gnome: Glimmerdust, Faeries' Murmur, Pile of Seeds, Petals (Red, White, Orange, Blue, Purple)
Gardening Gnomes: Glimmerdust, Faeries' Murmur, Pile of Seeds, Petals (Red, White, Orange, Blue, Purple)
Fawnicorn Pond: Energy, Fish, Red Fish, Blue Fish, Butterfish, Catfish, Water, Swamp Water, Algae Water, Fuzzy Moss, Mermaid Scales, Thurston's Helmet, Lost Page, Direboar (monster), Fey Crystal (rare)
Puddle Pig: Golden Apple, Chocolate Truffle, Bacon, Fangbeast (monster)
Sheep Shade: Fertilizer, Golden Fleece, Red Ribbon, Wool, Fangbeast (monster)
Spring Treeple: Wooden Beam, Patch of Tall Grass, Plant in a Log, Wood, Sap, Living Wood, Petals (Red, White, Orange, Blue, Purple)
Pig Pen: Decoration