For second-order elliptic partial differential equations large discontinuities in the coefficients yield ill-conditioned stiffness matrices. The convergence of domain decomposition methods (DDM) can be improved by incorporating (numerically computed) local eigenvectors into the coarse space. Different adaptive coarse spaces for DDM have been constructed and used successfully. For two-level Schwarz, FETI-1 and BDD methods, adaptive coarse spaces with a rigorous theoretical basis are known for 2D and 3D. Although successfully in use for almost a decade, a theory for adaptive coarse spaces for FETI-DP and BDDC was lacking. While the problem was recently settled for 2D, the estimate for the 3D adaptive algorithm required improved coarse spaces. We give an brief overview of the literature, i.e., the different known approaches, and show numerical results for a specific adaptive FETI-DP method in 3D, where the condition number bound could only recently be proven. Domain decomposition methods (DDM) are fast parallel iterative solution methods for the solution of implicit linear or linearized systems from the discretization of partial differential equations (PDEs). The convergence theory of these methods typically relies on a (global) condition number bound constructed from local theoretical estimates for finite element functions. Recently, new approaches have gained interest where these estimates are replaced by computable spectral bounds, e.g., from discrete local eigenvalue problems. A corresponding enrichment of the coarse problem then yields a global bound which only depends on a user-defined tolerance and some geometric bounds, e.g., the maximum number of edges or faces of a subdomain. Thus, convergence is not affected by ill-conditioning, e.g., from heterogeneities or (in some approaches) from almost incompressibility.Already in [2], spectral information, i.e., the eigenvectors corresponding to the smallest eigenvalues of subdomain matrices, has been used with Neumann-Neumann methods, heuristically. In 2007, in [17], adaptive coarse spaces for FETI-DP and BDDC domain decomposition methods were proposed for 2D problems, at this time without a theoretical bound. Later, an adaptive coarse space for additive Schwarz methods was proposed [7,8], based on eigenvalue problems on complete subdomains, replacing a Poincaré estimate. In [18], the strategy from [17] was extended to 3D and used very successfully, also in a parallel implementation. Later, coarse spaces based on local Dirichlet-to-Neumann maps were introduced for Schwarz preconditioners [6]. Then, for FETI-1 and BDD methods, a related adaptive approach was introduced [20]. At about the same time, published in [15], an adaptive approach for FETI-DP and BDDC methods was introduced by replacing a Poincaré inequality and an extension theorem (on edges) by eigenvalue problems; see [13] for the complete theory in 2D.Only recently, in 2015, for the first time a rigorous condition number estimate was then proven in [14] for the widely used adaptive approach from [17], fo...