Since there is no official Season 8, this is purely speculation based on the storylines of previous seasons:

• The World Serpent Rises: Building on hints from prior seasons, a major threat could emerge – the World Serpent, a colossal creature from Norse mythology. The riders might have to unite the Nine Realms and their dragons to confront this ancient evil.
• Testing the Dragon Pacts: The established pacts between humans and dragons could be challenged by external forces or internal conflicts. The riders might have to demonstrate the true value of their bond with their dragons.
• Next Generation of Dragon Whisperers: As Tom refines his skills as a Dragon Whisperer, he could mentor younger children, fostering a new generation of dragon riders who understand the importance of co-existence.
• Focus on Specific Dragons: The season could delve deeper into the personalities and abilities of lesser-featured dragons like Feathers (Alex’s dragon) or Zippy (D’Angelo’s dragon), showcasing their unique contributions to the team.
• Sledkin’s Fate: Sledkin’s past actions might finally catch up to him. The riders could expose his wrongdoings, or he could face consequences orchestrated by other characters.