I keep my landing arsenal pretty simple.
Gaffs: I carry 2 gaffs. The first is a 60″ gaff that is my primary gaff. I know a lot of anglers prefer a 6’ gaff so they get extended reach but I prefer the shorter gaffs. For starters, I prefer getting closer to the fish to ensure a nice, clean head shot so that I do not damage the meat. The second reason, and really the more important one as far as I am concerned, is that it is much easier to deal with around the boat when not using it and also when landing the fish. You have less pole flying around batting at your crew when you are landing the fish. I carry the second 48” gaff for help with a large fish once it is gaffed.
Harpoon: I carry a Poon Harpoon that I have had since 2008. I have mine rigged with 100’ of 3/8”¼” nylon rope. I am not targeting fish over 300lbs with casting and jigging gear so that amount of rope is OK. If targeting larger fish, you may want to carry as much as 300’ of line.