Some of the tools that make my life easier at work are:
WIRESHARK: Wireshark is a free and open-source packet analyzer. It is used for network troubleshooting, analysis, software and communications protocol development, and education. (Careful, must have written consent from CEO before using)
Kali-Linux: Kali Linux is a Debian-derived Linux distribution designed for digital forensics and penetration testing. It is maintained and funded by Offensive Security Ltd (Careful, must have written consent from CEO before using)
Angry IP Scanner: Angry IP scanner simply pings each IP address to check if it’s alive, then optionally it is resolving its hostname, determines the MAC address, scans ports, etc. The amount of gathered data about each host can be extended with plugins.
Recuva: Recuva is an undeletion program for Windows, developed by Piriform. It is able to undelete files that have been marked as deleted; the operating system marks the areas of the disk in which they were stored as free.