Cloud Tasks depend on a GAE project running on a specific region. The app serves as the location for whatever queues are created.
On Kubernetes, you can run Jobs or Cron jobs. However, there are differences between these options and App Engine Tasks Queue.
This and this show that Knative offers eventing functionalities that Kubernetes does not have built in (it runs on top of Kubernetes). However, as per the Knative Event description documented here and here, it does not seem to share many similarities even though it might be an alternative depending on your use case. In regards to other alternatives, I would suggest you check Cloud Run (currently in Beta) and Cloud Scheduler as they might also comply to your use case.