Obviously there is shape....
Cushion Shaped (Panerai, Anonimo etc.)
Rectangular (JLC Reverso, Bell & Ross etc.)
Tonneau (Cartier Roadster etc.)
There is also Functions...
Chronograph
GMT
Alarm
Day, Date
Annual Calander
There are also other Brands
Anonimo
Audimars Piguet
Bell & Ross
Breguet
Cartier
Chopard
Daniel JeanRichard
Girard Perregaux
Grand Seiko
Hublot
Montblanc
Officine Panerai
Omega
Rolex
Ulysse Nardin
Vacheron Constantin
Zenith
If I filter by In-House movements, the Universe narrows a bit (I added existing brands with an asterisk)
Audimars Piguet
Blancpain*
Breguet
Cartier
Chopard
Daniel JeanRichard
Girard Perregaux
Glashuette Original*
Grand Seiko
Hublot
IWC*
Jaeger-LeCoultre*
Montblanc
Officine Panerai
Omega
Rolex
Vacheron Constantin
Zenith
Easy to set when among 6 watches...
Date complications add another step so that is something to consider whereas a chronograph or GMT may not.
A sports watch...
Something that one can wear when taking a swim and not be concerned if it sees some water. Those of you who suggested a vintage Rolex Sub, I have a diver with the IWC and do not want to duplicate at this time.
So since day date, annual calendar add set up steps, I think I will pass on those. That perhaps leaves chronograph and GMT watch functions (maybe others). On the shape front the cushion shaped watches seem to be in general more water resistant (I believe Reversos, even Squadras are 50 m rated).
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