Which different EDL types exist?
CMX 3600 (or earlier 340) is very common and understood by many systems. GVG (Grass Valley Group) format is almost as common. For simple cuts, dissolves and keys the two are highly compatible, but for more complex edits, including speed changes, there are significant differences. Neither deals well with multiple layers or multiple sources in one event.

Many other companies use proprietary formats that are often only slightly different from basic CMX/GVG. Things like the size and contents of the source ID, the use of notes for special effects, and so on, may change from version to version as well.

To list the specifications would take a very long post. If you have specific questions about what each can handle, try asking here. But in general, for interchange you'll probably find XML-based EDLs to be most flexible, and CMX/GVG will be understood by the most different systems, within their limitations.

Google "EDL XML AAF" for a lot more information on the topic.