French 75 (use good champagne)
French 76 (use good champagne)
Old fashioned (use expensive cherries)
Side car (use orange brandy instead of orange liqueur)
Manhattan (don't skimp on bitters)
Cosmopolitan (throw the used lime into the shaker)
Whiskey sour (use egg white)
Gimlet (add a cedar leaf for more flavor)
You can use Acquafaba instead (chick pea water). That actually works at least just as well, no taste, perfect texture. Many barkeeps prefer it from what I hear.
Try it before deciding. It's really good. Dry shake first, then put ice and shake again. I'll take a whiskey sour any way someone wants to make it, but for an amaretto/bourbon sour an egg white is essential, it is so much better with it than without.
My absolute favorite is New Your Sour (Basically Whiskey Sour with a dash of red wine (and slightly different mixing ratios.
Last time I made them with Acquafaba (basically bean water; the water you get from a can of chick peas) instead of egg white and let me tell you, that worked like a charm, can only recommend!