Sorry about the lack of information
It seems to me that previous comments attempting to answer your question are failing to understand exactly what you are asking. Every answer has been related to you going to the part store and renting the crappy poorly designed fan clutch removal wrench set. In my personal opinion, I hate the removal tool kit. They are outrageously expensive and poorly designed in my opinion. If you are simply trying to find a good wrench that will fit the fan clutch "nut" and you already have a backup wrench or something else to do the same job of holding the fan clutch while you brake the nut loose, then I can answer your question the best I can.
Most of the clutch fan nut sizes that I have come across on both Ford and GMC vehicles have been size 1''7/8. I recently replaced a water pump in an early 2000s model Ford 1 Ton Turbo diesel engine and the clutch fan nut size was 1''7/8. The newer model Chevy Vortec engines that I have taken apart and repaired have all been the same size as well. The other size that I have encountered have all been smaller than 1''7/8, but I cannot remember exactly what size wrench they required specifically. However, a good 1''7/8 wrench should do the job for you just the same. That size seems to me to be the most common.
Tip: If you ever have trouble holding onto the fan clutch while you break the nut loose, these boogers can be quite tight and a pain in the butt to hold well enough to apply a fair enough amount of force to break the nut loose, I have a helpful little trick that might come in handy for anyone reading this post. Take the drive belt completely off of the engine where the surface of the water pump pulley is bair. Then, get a small sized ratchet strap and secure one end somewhere on the inside of the fender, towards the top of the engine. Then, bring your strap down and make one wrap around the water pump pulley and bring the other end of the strap to the top of the engine and secure it to the opposite fender. Tighten the ratchet strap up good and tight making sure that the strap is not binding up on anything in its path that will break when it is tightened up. This may just give you that little bit more hold on the fan clutch that you need to break the nut loose.
