Chives (Allium schoenoprasum) would be a great companion with your Pineapple Sage. Chives, in the spring, will bloom an attractive light purple flower and these are excellent in salads.

pineapple sage is so invasive and gets so huge, I like to keep it to itself--everything in my garden is pretty close together--I like the jungle effect, but I wouldn't give it a "buddy" in the garden. I do like the idea of something little and blue in front of it, but I don't think there's anything that would be of mutual benefit.