[pa7x1]

Yes, and even 1+1 gravity theories, like JT-gravity (https://en.wikipedia.org/wiki/Jackiw%E2%80%93Teitelboim_grav...).

But 2+1 Einstein's gravity is locally trivial (i.e. there are no local degrees of freedom) and is purely topological (i.e. holes and global structure of spacetime is what matters).