I'm not playing one at the moment (too much on) but ones I have played and enjoyed in relatively recent times are:
The rules from the Tomb for an Empire boardgame: link
The rules from the Polemos Napoleonic companion: link
The generalship game in Paddy Griffith's Napoleonic Wargaming for Fun: link
Various rules from magazines. The ones from the top of my head…
Henry Hyde's rules in Battlegames magazine: payhip.com/b/LU1d
George Gush's rules in Miniature Wargames 31
Steve Jones' rules in recent-ish Miniature Wargames. I think his Waterloo ones were in 386, he has also done some for the Danube campaign.
Paul Leniston's campaign rules: link
A lot will depend upon the size of forces and how long you want a campaign to run I think and how much you want to emphasize the role of supply versus tactical manoeuvre.