Extra secrets created when helm is used
Helm v2 used ConfigMaps by default to store release information. The ConfigMaps were created in the same namespace of the Tiller (generally kube-system).
In Helm v3 the Tiller was removed, and the information about each release version had to go somewhere:
In Helm 3, release information about a particular release is now stored in the same namespace as the release itself.
Furthermore, Helm v3 uses Secrets as default storage driver instead of ConfigMaps (i.e., it's expected that you see these helm secrets for each namespace that has a release version on it).
There is an option to helm upgrade to limit the number of old deployment secrets that are kept:
--history-max int limit the maximum number of revisions saved per release. Use 0 for no limit (default 10)