Methods, apparatus and articles of manufacture to provide client extensibility during provisioning of virtual computing resources are disclosed. An example event broker apparatus includes a subscription manager to manage subscriptions to event topics associated with provisioning of a virtual computing resource. The example apparatus includes a meta-topic subscriber to identify a subscription request by a service for an event topic and to trigger, in response to the subscription request, a meta-topic subscription to indicate a) a subscriber to the event topic and b) a type of the subscriber, the type to include at least a blocking subscriber. The example apparatus includes a topic monitor to monitor for an event corresponding to the event topic to determine whether to trigger a blocking subscriber workflow when the meta-topic subscription indicates that the type of the subscriber is a blocking subscriber or bypass the blocking subscriber workflow when the type of the subscriber is not a blocking subscriber.