Below are a brief set of definitions as far as ETC is concerned.
Cat3 = old telephone wire and ETC does not use it, probably never did.
Cat5 = 100M/s (Fast Ethernet) for 100m, 1G/s (Gigabit Ethernet) for 50m. Obsolete but older installations may have cable and connectors at this rating.
Cat5e = 1G/s for the full 100m. ETC's current level for standard installations. Still good but has been around for a long time, still the go to cable at this point. ETC devices with etherCON connectors use the 5e version.
Cat6 = 1G/s for full 100m but 10G/s for 50-55m. Good but not used too much now that 6a has been out for a while. Generally the cable, jacks, and patch cables are more expensive than Cat5e. The Neutrik Cat6 etherCON jacks are not compatible with the Cat5e or Cat6a etherCON parts and they are harder to terminate. ETC does not recommend these. Special custom cables with different connectors on each end would be needed.
Cat6+ is seemingly a marketing thing from some cable makers to say that it is a bit better than Cat6 but doesn't meet the 6a standard. Will be treated as cat6.
Cat6a = 10G/s for full 100m. This is gaining popularity and will eventually take over cat5e. Generally the cable, jacks, and patch cables are more expensive than Cat6. The etherCON versions are compatible with the Cat5e ones.
Cat7 = sort of exists, there is a standard but no one makes connectors yet. The wire does exist. It reportedly won't be backwards compatible with the 3-6a standards.
If you have questions contact ETC at firstname.lastname@example.org.