What is in the Fossils collection in The Sims 4?

Sims 4 Fossils collection: every item

The Fossils collection in The Sims 4 has 15 items: 9 common, 3 uncommon, and 3 rare. 5 bonus items don't count toward it.

Every item

The 15 items of the Fossils collection
Item	Rarity	Catalog value
Enormous Trilobite	common	§40
Fossilized Egg	common	§70
Fossilized Plant Imprint	common	§70
Fossilized Sea Monster	common	§50
Fossilized Sim Hand	common	§45
Hilariously Tiny T-Rex Arms	common	§45
Pre-Historic Hoofprint	common	§40
Prehistoric Rock	common	§15
Raptor Claw	common	§70
Fossilized Udder	uncommon	§85
Perfectly Preserved Mustache	uncommon	§100
Prehistoric Bird	uncommon	§75
Fossilized Alien Skull	rare	§250
Fossilized Whatzit	rare	§175
Pre-Pre-Pre Sim Head	rare	§225

The catalog value is the base price the game gives the object. Rarity decides how often it turns up.

These 5 items belong to the collection but don't count toward finishing it.