Various 15mm manufacturers are on the market. As fas as I know, the following 15mm ranges are available.
French, British and Indian (Tippo Sahib period) . The French range is usable from 1792 up to1802. Almost all needed figures are there. The same can be said of the British range; early and later period is there. The earlier (bicorn wearing) troops could also be used for the Hanoverian corps of 1793-1795. The Indian range look reasonably complete; photos are available of this Indian range so goto http://www.miniaturefigurines.co.uk .
In other Minfigs ranges, usable figures can be found as in the Russian Napoleonic range (early figures for the 1799 campaign), AWI range (for German troops) and 7YW range (some Austrian could, according to Minifigs used for the French Revolution; I haven't seen them, so cannot comment). Also 1809 Saxon could be used as 1792-1795 Dutch.
The only comment I have against the French/British range is, that they almost all are in the lunge forward (wow, I almost topple over) figure pose which I don't like. But, they are the only British/Hanoverean range for the earlier years of the revolution. All in all, you have to like the Minifigs style.
Go to http://www.essexminiatures.co.uk/frames15nap.html to see the range (with pictures af all the figures).
Only small range of mostly infantry, other figures can be drafted in of the Napoleonic (aarly period figures), AWI and SYW ranges.
I like the infantry figure in tarleton, a dignified "Blanc" but imho not usable for the later "Blue" in tarleton. But the tarleton command with eagle is stupid.
The mounted general command figures are good but their horses are not as good.
Magister Militum (ex chariot)
The ex-chariot range has some very good figures; the early enthousiastic figures and the "Paris mob" give revolutionary flair. The range is not complete although most french troops are there. The (only available) Prussian range give some basic troop types (although the grenadier is of the 1806 period) as does the Austrian one. In 15mm a good range with noticable gaps. Some figures are below.