Indefinite frequency adverbs are adverbs that indicate how often an action occurs without specifying an exact frequency. Some examples of indefinite frequency adverbs include:

1. Sometimes
2. Occasionally
3. Frequently
4. Rarely
5. Often
6. Seldom
7. Usually
8. Generally
9. Regularly
10. Infrequently

These adverbs provide a general idea of how often an action takes place without specifying a specific number or frequency.