Yes there is. As of now there are several alternatives like the set from Insurrection Industries. There is also the GCHD Mark II with all-in-one HDMI and component video compatibility.
as i said in my post indi alternatives however those are around 70 100$ + these are not what one would consider the cheap 5$ 3rd part cables like with other consoles thanks to the way the gamecube was made.
again why I'm thinking that the original component cables are mainly a collectible at this point since there are other options al be it just moderately cheaper and only for the gameboy player if where speaking of usage since gamecube games can just be used on a wii console.
not to mention that the original cables only slightly increased in price last couple of years not gone down even though we have other options so i don't think usage covers the full price in this case. rare hardware that is collectible or used for purist as my only explanation
also for a crt the gamecube's original scart cable might be better.