General:
* Awesome: This is a very common and versatile term, used for anything from a great song to an amazing meal.
* Rad: This term is a bit more dated, but still frequently used, particularly by younger generations.
* Sick: While this word can mean ill, it can also mean excellent, particularly in skateboarding and other youth cultures.
* Dope: This is a popular term, often used for things that are cool or impressive.
* Epic: This word is used for events or experiences that are truly remarkable.
* Brilliant: This term is more formal, but still slangy.
* First-rate: A more old-fashioned term for excellent.
* Top-notch: A formal term that implies high quality.
* Stellar: This word emphasizes the quality of something, often used in relation to performance.
Regional:
* Wicked: This is a common term in New England and parts of Canada, meaning excellent or really good.
* Ace: This is a term popular in the UK, meaning excellent or first-rate.
* Knackered: This British term, meaning "exhausted", can also be used ironically to mean "excellent" in some situations.
* Brilliant: This term is used widely in the UK and Australia, meaning excellent or superb.
More informal:
* Boss: This term, often used to describe something cool or impressive, can be used to express excitement.
* Amazing: This term emphasizes the impressive nature of something.
* Fantastic: This term is a bit more formal than "awesome," but still very common.
* Superb: This word is a bit more formal than "excellent," but still very strong.
* Splendid: This term is very formal and suggests a high level of quality.
The best term to use depends on the situation and the speaker's personal preferences.