Rules are delivered as part of BC Sets (Note: Activating BC sets will overwrite the current rules)
Latest rulesets are available in the latest Support Pack for SAP Access Control.
Activate the required BC Set Rulesets from transaction SCPR20.
Activating BC sets will overwrite current rulesets data if you have one already. To get the standard rulesets again, download the existing rules (Go to SPRO =>Governance, Risk and Compliance =>Access Control =>Access Risk Analysis =>SOD Rules =>Download Rules) as a backup and then activate BC sets (DEV system ONLY). Now download the ruleset again and do a delta comparison. Once rulesets changes are compared and updated as per your requirement, upload the new ruleset from SPRO again.
You can upload the rules from SPRO. Go to SPRO =>Governance, Risk and Compliance =>Access Control =>Access Risk Analysis =>SOD Rules =>Upload Rules.
It is recommended to upgrade your dev system to latest SP to get the latest BC Set content.
You can also refer the KBA 1663370 - Rulesets for SAP Access Control