Based on official Kubernetes documentation there should be no limit of independent labels in pod. But you should know, that each valid label:
- must be 63 characters or less (can be empty),
- unless empty, must begin and end with an alphanumeric character ([a-z0-9A-Z]),
- could contain dashes (-), underscores (_), dots (.), and alphanumerics between.
If you want to know where the 63-character limit comes from, I recommend this thread, RFC-1223 and explanation.
And Leroy well mentioned in the comment:
keep in mind that all this data is being retrieved by an api.