The most profitable niche markets usually fall into 1 of 3 markets, including:
Sex: Relationships, self-improvement to look and feel more attractive and more confident. This involves everything from weight loss, how to get your ex back, to e-learning.
Wealth: Making money, living a happier, stress-free life. This market includes everything from affiliate marketing to self-starters.
Health: Living a healthy, long life. This includes everything from acne prevention, healthy recipes, to yoga.