Here's my list of helpful CLI commands for Fortinet stuff (all published in the Fortinet Doc Library. I'll keep adding to this over time.

FortiGuard

• diagnose autoupdate versions - Lists the status of FortiGuard DBs and engines installed.

Routing

• get router info routing-table all - Displays all entries in the routing table.
• get router info kernel - Lists the routing table for the Forwarding Information Base (FIB); essentially the routing table form kernel perspective from kernel perspective.
• show full | grep src-check - Searches through configuration settings to see the value of the set strict-src-check setting (e.g. disable or enable)