In my opinion, starting with a catalog of places, creatures, treasures, spells, etc is great way to to build up lore for my game worlds. I anticipate developing one or more catalog systems. The first thought in my head, is using a Data Table (Local) | MySql Data Table (Remote), User Defined Type | Object Class (Immediate) and a UMG GUI to display the Stats and info. I can easily visualize re-purposing a Inventory System (one of many available in the Unreal Marketplace) to quickly provide a subsystem + UI to handle this functionality.
When when a Player ‘learns’ about a Creature, a key (name or integer id) is added to their inventory in which a query on the key will retrieve info on the Creature.