Nylon / ABS Current Transformer
Likely used for applications where moderate protection, lightweight, and insulation are needed.
Nylon / ABS + Resin Cast Current Transformer
These would be more rugged than just the Nylon/ABS ones.
Rectangular Resin Type Current Transformer
The shape suggests possibly bar-primary rectangular core, or rectangular window CTs.
Resin Cast Round Current Transformer
Probably used where the conductor is round, and where protection from dust.
Wound Primary Resin Cast Current Transformer
Useful for applications needing precise ratios, perhaps for more accurate metering.
Tape Insulated Round Current Transformer
Good where space or flexibility in mounting is needed where cost constraints exist.