This is a very good video about Sysinternals Tools. In fact, when I watched it months ago, I learned some new things about these tool's capabilities.
However, I think the title of the video is a misnomer. Hunting malware commonly refers to finding new malicious samples (usually with a certain goal). Researchers are often looking for certain malware families or for samples of new malware families or new variants of known families. What Mark Russinovich does is rather identifying if a system is infected, what files, entries and processes belong to that infection, and how to clean the system. Whilst you could also get new samples by chance from an infected system, it is not the best way to actually hunt for malware, because in most cases you won't get what you are looking for.
What we do for hunting is:
- using large sample databases and YARA to search (e.g. on Virustotal)
- automatic analysis, e.g., reverse.it, malwr.com
Antivirus companies also have their own databases and automatic scanning procedures.