I have no idea what to do with the rest. E.g., vol-ef097386 from eu-west-1.
Not attached to anything. No tags. No reference in ansible.git. No
information.The only thing that comes to my mind is: make a snapshot, tag
the snapshot with FedoraGroup=snapshot-before-deleting, delete the volume.
If somebody will miss it, then restore it from snapshot. Otherwise delete
the snapshot after several months.

That sounds a good plan to me. That way if we break anything we can put
it back. 😉 

I have started doing that.

I want to be as gentle as possible so I am doing this manually and doing my best to identify somebody as owner.

Before I delete the volume I create snapshot with

Name: GC - snapshot of $volume-id

FedoraGroup: garbage-collector

-- 
Miroslav Suchy, RHCA
Red Hat, Manager, Packit and CPT, #brno, #fedora-buildsys