There are several types of collectibles to keep an eye out for as you travel between the Earl's Castle, the Ship Graveyard, and various islands:
Lost Lands: The Wanderer - Collectible Guide - PC - GameFAQs lost lands 4 collection items locations
Check the skull puzzle inset after solving the first "opposites crossing" puzzle. There are several types of collectibles to keep
Based on detailed guides from GameFAQs and Pro Game Guides , here are specific locations for some of the most elusive items: Earl's Castle & Surroundings the Ship Graveyard
Look on the left-middle next to the throne.
Specific objects like ship models or figurines tied to the game's lore.