Multitudes of ways. Whether they are faster or not is purely subjective.
- Grinding Player heads, the headless enchant actually works and also players drop heads almost every time if you use an alt you can grind out thousands of heads a day.
- Carrot/Potato farms are definitely the top tier of manual farming
- Mob Grinding wise Blazes are the most profitable for xp/heads/drops but you need something that can one hit them or a technique to make them one hittable.
- Mob farms: Iron Golems, Creepers and Evokers are definitely the most profitable a big part of this is what you've actually unlocked, Creepers aren't bad if you've got them now but you definitely want to be moving on to Iron Golems and Evokers as soon as you can.
Edit: Also make a bigger farm if you're not earning enough :)