Your budget is? If it’s a nominal one, go for a flower, a chocolate, a teddy, and maybe a pretty pair of earrings, or a neck piece, or some handmade gifts like card, scrap book or anything.
And if you aren’t worried about the budget then surely plan some good decor first, or u can just do basic foil balloon decor on ur own. With a bouquet, an amazing dress/top or pair of shoes/heels (if u know the sizes) or just go with some amazing jewels too. U can check @everstylish for jewels it’s reasonable and @snapstore for collage snap book etc they are reasonable and good too.