Blonde Ale is a flexible style, with a lot of possible additions, but some really bad combinations. It’s a very neutral palette that gives you a lot of room to play.
Ingredients like grapefruit, orange peel, lemon peel, and even juniper berries would likely work with the citrus flavor of a Blonde Ale.
Fruit additions are a possibility- think apple, blueberry, raspberry, blackberry, watermelon, and cranberry, or even some combination of several.
Floral additions may work, like elderflower, cucumber, and rhubarb.
A tart adjunct including lemon grass might pair in a Blonde Ale.
A Blonde Ale is an okay base style for a sweet adjunct. Flavors like chai and coconut would be a possibility.
Some more off the way ideas that have some potential are a boozy flavor like bourbon, or earthy ingredients like ginger and coffee. You could also try an herbal adjunct like green tea.
Since Blonde Ales don’t really a ton in the way of flavor, they are quite flexible, and you might even play mix and match with some of these suggested ingredients, like a blueberry rhubarb blonde ale, or a juniper berry and ginger blonde.
BJCP Style: 18A