General:
* Adornments
* Embellishments
* Trimmings
* Ornaments
* Festivities (when referring to celebratory decorations)
* Furnishings (when referring to decorative items within a home)
Specific to specific types of decorations:
* Accessories (for fashion or interior design)
* Bling (for sparkly, showy decorations)
* Garlands (for string of decorative items)
* Wall art (for decorative items on walls)
* Centerpieces (for decorative items in the center of a table)
* Table settings (for decorative items on a table)
* Props (for decorative items used in theatre or film)
More formal terms:
* Decorative elements
* Aesthetic enhancements
The best synonym to use will depend on the specific context of your sentence.