FEPP - Finite Element Simulation Code in C++.

NETGEN - 2D/3D Advancing Front Mesh Generator.

NGSovle is a general purpose 3D finite element solver.

NAOMI2D - Ferdinand Kickinger: An optimal 2D mesh-generator with Algebraic Multigrid solvers for potential equation and plain strain elasticity problems. Also adaptive Strategies are implemented (solution of local problems as error estimator).
For downloading the Software , you need a password from Ferdinand Kickinger.

PEBBLES - Parallel and Element Based grey Box Linear Equation Solver.