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All the (L for large) 42mm Leather Loop bands should work, (not Medium), Milanese loops too. You can get the Apple Link band and buy extra links too, if money is no object. not sure about the new Nylon Sport loops, haven't seen one. The loops have no buckles so they are infinitely sizeable.
 
Third party. Contact places like clockworksynergy.com to see what they can cook up for you.
 
I have large wrists too.
I have been limited to what I can wear.
Apple have XL sports bands in black or white (us with big don’t need colours)
The sports loop fit (just) I find getting it over my hard to be a problem.

The leather loops and Milanese loops are a light fit, but do fit just.

Then it’s the links With extra links £€$¥ and that’s it from Apple
 
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