If you twisted my arm and made me rank the themes, I'd say:

1. Signal
2. Overgrown
3. Absorb
4. Strange machines
5. Salvage
6. Tiny Creatures
7. Shelter
8. Sanctuary
9. Limited space
10. Paths
11. Folklore
12. Locks and keys
13. Underground
14. Reflect
15. Keep the light on
16. Break the cycle

Though (happily) I don't even mind if 16 wins, so... hyped for LD54!