Networking presentations encompass a broad range of topics from the general "What is a computer network?" to the specific "How do I do a replay attack with a network application?". You'll find most things that aren't application specific here.
Analysis and reverse engineering includes facets of how to determine the inner workings of a compiled or obfuscated system. Examples include how to determine what a particular malware does and how to create your own implementation of a network protocol.
Penetration testing is using various tools to gain access to or information from systems that are otherwise not available to you. This include using Metasploit to get a shell on a vulnerable system and how to pull back database data using SQLMap.
Information gathering is using any means necessary to learn more about a particular system or environment. It touches on topics such as enumerating a computer network and what information is important to keep in a consulting scenario.
Virtual machine presentations encompass information on running hypervisors to other forms of virtualization such as Docker containers.
Linux OS topics are found here. This includes features such as shell script or how to configure the OS.
All things Windows are found here. This includes quite a few presentations about using PowerShell effectively.
Miscellaneous presentations are those that are not core subjects. These include small interesting presentations, club related presentations, and things that are useful but not a full presentation.