one very useful tool for tagging and tag governance, is https://github.com/cloud-custodian/cloud-custodian you can setup policies to auto tag things with creators, and enforce tag policies, enforce valid vocabularies, and work through remediation and notification workflows. There's even a standalone tool to do retro-active tagging on resource creators via cloud trail querying (c7n_trailcreator).
disclaimer: maintainer on cloud custodian