In the Third Edition Player's Guide the most damaging two-handed weapons that Trolls can use are also usable by Humans. Kind of pointless being three times as heavy and half again as tall if you are limited to the weapons of the small ones.
Are there bigger weapons in other books?
Namegivers of Barsaive has an extensive list of weapons appropriate for large (obsidimen and trolls) and small (windling) races. The basic formula to derive the damage step for a standard weapon of any size is Size + 2. This assumes it doesn't do anything interesting. Flowing blade is an exception and honestly too powerful.
The big advantage for trolls is that they can use larger weapons in one hand, allowing them to use a large weapon and also get a shield. Makes them super durable while still keeping damage up.
I think there are none. Looking at the First edition, the fact that Humans can use the same weapons as Trolls seems to be intentional.
Illogical but probably more balanced.
