Squire model 660, widely available, not expensive, can be keyed alike if you have several sheds).
(they sell the same design in smaller models)
It has a galvanised steel case, the internal workings are brass levers, quite large and do not bind or corrode.
Water drains through it.
Lasts for scores of years.
Never had one stop working.
The steel hook is quite substantial.
You can throw it in a bucket of paraffin ever ten years or so to wash out dirt.
You can spray the outer galvanised case with paint to prevent it getting shabby.
For more valuable lockups, you can get the ERA and similar 6-lever big padlocks. Again, the brass levers don't rust and the outer is steel. Sometimes
Wickes sell ERA locks as own-brand, but you'll find the maker's name stamped on the keys.
You can still get the old Chubb models (now branded Union) as used on jewellers shutters, but they cost a hundred or more.
Squire
ERA
Union (Chubb)
there are other brands that might be cheaper, but check the specification for brass levers and bronze or stainless internal springs.
IME lever locks last much longer than cylinders, and have fewer weaknesses.