  New low-order $H(\textrm{div})$-conforming finite elements for symmetric
tensors are constructed in arbitrary dimension. The space of shape functions is
defined by enriching the symmetric quadratic polynomial space with the
$(d+1)$-order normal-normal face bubble space. The reduced counterpart has only
$d(d+1)^2$ degrees of freedom. Basis functions are explicitly given in terms of
barycentric coordinates. Low-order conforming finite element elasticity
complexes starting from the Bell element, are developed in two dimensions.
These finite elements for symmetric tensors are applied to devise robust mixed
finite element methods for the linear elasticity problem, which possess the
uniform error estimates with respect to the Lam\'{e} coefficient $\lambda$, and
superconvergence for the displacement. Numerical results are provided to verify
the theoretical convergence rates.
