Keep an archived version of it somewhere in case people inquire / need it later.
Notes:
Data migration sensitive data migration is a PDF that I can't find available anywhere else on GSA web properties, that can go too.
RPA playbook is unique content but not valuable, that can go too.
TBM is not a methodology GSA still follows, that playbook can go.
Remove all playbooks except for unique authored content:
Keep an archived version of it somewhere in case people inquire / need it later.
Notes: