Admittedly, I haven’t put much time into this yet, but I do like how, from the Room of Requirement, you can step right into a vast vivarium that serves as a new home for the creatures you’ve collected.

Source: https://kotaku.com/hogwarts-legacy-review-harry-potter-rowling-transphobia-1850127849

Dittany Leaves might be noticed whereas exploring the sport’s open world map or grown in both the Room of Requirement or Herbology Class greenhouse.

Source: https://www.mccourier.com/how-to-obtain-wiggenweld-potion-in-hogwarts-legacy/

It may be picked up from Deek, the home elf, within the Room of Requirement.

Source: https://www.mccourier.com/how-to-complete-phoenix-rising-side-quest/

Since the room becomes available after completing a good chunk of the main quests, it is possible to plant the Mallowsweet in the Herbology Classroom’s Pot temporarily and wait for the Room of Requirement quest to trigger.

Source: https://gamerant.com/hogwarts-legacy-get-mallowsweet-ingredient-merlin-trial/

While most of these creatures can be captured and returned to the Room of Requirement, a select few will become aggressive when approached.

Source: https://gamerant.com/hogwarts-legacy-how-to-levitate-dugbog-by-its-tongue-duelling-feat/