  We introduce a computational method and a user-friendly code with a
terminal-based graphical user interface (GUI), named ElATools, developed to
analyze mechanical and anisotropic elastic properties. ElATools enables facile
analysis of the second-order elastic stiffness tensor of two-dimensional (2D)
and three-dimensional (3D) crystal systems. It computes and displays the main
mechanical properties including the bulk modulus, Young's modulus, shear
modulus, hardness, p-wave modulus, universal anisotropy index, Chung-Buessem
anisotropy index, log-Euclidean anisotropy parameter, Cauchy pressures,
Poisson's ratio, and Pugh's ratio, using three averaging schemes of Voigt,
Reuss, and Hill. It includes an online and offline database from the Materials
Project with more than 13,000 elastic stiffness constants for 3D materials. The
program supports output files of the well-known computational codes IRelast,
IRelast2D, ElaStic, and AELAS. Four types of plotting and visualization tools
are integrated to conveniently interface with GNUPLOT, XMGRACE, view3dscene,
and plotly libraries, offering immediate post-processing of the results. It can
efficiently identify anomalous mechanical properties, such as negative linear
compressibility, negative Poisson's ratio, and highly-anisotropic elastic
modulus in 2D and 3D materials, which are central properties to design and
develop high-performance nanoscale electromechanical devices. Six case studies
on selected material systems, namely, ZnAu$_2$ (CN)$_4$, CrB$_2$,
$\delta$-phosphorene, Pd$_2$O$_6$Se$_2$ monolayer, and GaAs, and a hypothetical
set of systems with cubic symmetry are presented to demonstrate the descriptive
and predictive capabilities of ElATools.
