My level 7 drow bard is pretty much fully optimized what uncommon item should I buy?

Your DM lets you choose your own magic items at 7th level?! Huh. Don’t tell my players. #wotcstaff P.S. Hat of disguise or immovable rod. https://t.co/bOy9VxqIUB

— Christopher Perkins (@ChrisPerkinsDnD) June 9, 2017