Here are some options, depending on the context:
* Council: This suggests a group of elders who meet to advise or make decisions.
* Assembly: This implies a formal gathering of elders.
* Patriarchs/Matriarchs: This specifically refers to elders who are heads of families or communities.
* Seniors: This is a general term for people who are older.
* Eldership: This is a more abstract term that refers to the position or status of elders.
You could also use a descriptive phrase like "a gathering of wise elders" or "a group of respected elders".
Ultimately, the best collective noun depends on the specific context and the message you want to convey.