The following is a short list of main attributes of Chrono.

Physics modeling

Rigid body support.
Flexible body support - both for ANCF and co-rotational nonlinear finite element analysis.
Support for fluid-solid interaction problems, via Chrono::FSI module.
Coulomb friction model capturing stick-slip phenomena.
Support for rolling friction and spinning friction.
Support for handling frictional contact via two approaches: a complementarity approach and a penalty approach.
Springs and dampers with non-linear response. Can be user defined.
Large collection of joints and constraints: spherical, revolute, prismatic, universal, glyph, screw, bevel and spur gears, pulleys, etc.
Unilateral constraints.
Constraints to impose trajectories, or to force motion on splines, curves, surfaces, etc.
Constraints can have limits (ex. elbow).
Constraints can be rheonomic or holonomic.
Custom constraint for linear motors.
Custom constraint for pneumatic cylinders.
Custom constraint for motors, with reducers, learning mode, etc.
On the fly constraint activation/deactivation.
Simplified 1D dynamic models. Examples: powertrain, clutches, brakes, etc. For more sophisticated models see the Chrono::Vehicle module.
All physical items can have an arbitrary number of 'assets' used for defining visualization shapes, custom properties, etc.

Solver

HHT solver for index 3 differential algebraic equations.
Symplectic first order half-implicit Euler solver for large frictional contact problems.
Speed-impulse level solver for handling large frictional contact problems.
Handling of redundant/ill posed constraints.
Stabilization or projection methods to avoid constraint drifting.
Static analysis solver.
Inverse kinematics and interactive manipulation.

Supports compounds of spheres, cubes, convex geometries, triangle meshes, etc.
Additional collision support provided by the Bullet collision detection engine, which is wrapped inside Chrono::Engine.
Broad phase collision detection: sweep-and-prune SAT.
Narrow phase collision detection: AABB and/or OBB binary volume trees.
Detail phase with custom primitive-to-primitive fallbacks.
Safety 'envelope' around objects.
Report penetration depth, distance, etc.
Bodies can be activated/deactivated, and can selectively enter collision detection.

Eigen-based matrix and vector operations.
Optimized custom classes for vectors, quaternions, matrices.
Optimized custom classes for coordinate systems and coordinate transformations.
All operations on points/speeds/accelerations are based on quaternion algebra.
Special archive engine, with easy and reliable persistent/transient serialization.
Expandable run-time class factory.