If you struggle finding a theme for Nexus, think that the themes we had for now where based from countries (japan, africa), eras (cowboy, retro, space (futuristic)), or themes (sport, food, games (rpg),tales).

The team won't also take a theme that sound too close from one they already made because of the lack of content that is now possible to make
There is also some themes that cannot be made because we already saw them in revolution or different events (20century wars, prehistoric stuff, Egyptians...)

If i had to give some ideas from what I explained :

- maybe a world Nexus, like making a travel around the world and buying the most famous hats, foods and more of countries as Brazil, India, Australia, France, Kenya

-An industrial themed Nexus wich you would regroup with a steampunk Nexus

-A small world Nexus like if we became small as the size of an insect and went discovering the garden and kitchen