Remember, these tools may miss items and it's good to go over the box manually as well.
LinPeas: https://github.com/carlospolop/privilege-escalation-awesome-scripts-suite/tree/master/linPEAS
LES (Linux Exploit Suggester): https://github.com/mzet-/linux-exploit-suggester
Linux Smart Enumeration: https://github.com/diego-treitos/linux-smart-enumeration
Linux Priv Checker: https://github.com/linted/linuxprivchecker