| Clue | Source | Date |
|---|---|---|
| Once in a blue moon | Universal | 08 Jul 2025 |
| Seldom: 2 wds. | Commuter | 14 Mar 2024 |
| Infrequently | USA Today | 20 May 2022 |
| Seldom | Eugene Sheffer | 18 Nov 2021 |
| Seldom | Eugene Sheffer | 24 Sep 2020 |
| Infrequently | New York Times | 24 Feb 2019 |
| Infrequently | ||
| Once in a blue moon | ||
| How consonants appear in this puzzle's theme entries | ||
| Rarely | ||
| Seldom | ||
| Rarely | ||
| Once in a while | ||
| Rarely | ||
| Rarely. |