I think the best answer is: It depends.
Each use case might need a self tailored convention.
The more teams that use the same Jenkins, the more complex the convention has to be in order to manage properly Roles and Permissions.
You can also lookup for Java/C#/python/powershell naming conventions to find useful ideas if you want to create your own convention.
In general, I would go for PREFIX_Name_SUFFIX:
- PREFIX: [a-zA-Z0-9]{3,5} (might be skipped if complexity level is low)
- Name: [a-zA-Z0-9-]+
- SUFFIX: [a-zA-Z0-9]{3,5} (might be skipped if complexity level is low)