For reporting, the ones I use to get security/blocking related events are...
https://developer.cisco.com/meraki/api-v1/get-network-events/ with filters to select just the event types I want, for instance...
aiomeraki.networks.getNetworkEvents(net['id'], productType="appliance", includedEventTypes = ["nbar_block", "cf_block", "sf_url_block", "sf_binary_block"], perPage=1000, total_pages="all")
See this for the current list of event types... https://developer.cisco.com/meraki/api-v1/get-network-events-event-types/
...note that the return format/content varies depending on event type, I don't think it's definitively documented, I ended up gathering lots of events to work out the format of the ones I was interested in, there can also be different formats for the same event type.
But not all events are 'events' 😀 This call is also needed...
https://developer.cisco.com/meraki/api-v1/get-organization-appliance-security-events/
....there's a network-level version of this too...
https://developer.cisco.com/meraki/api-v1/get-network-appliance-security-events/
I actually prefer the network-level version, as the org-level one doesn't include the network ID in responses (which IMO it should!)