In this review, we set out to present a detailed and comprehensive comparison between individual tough hydrogel systems. Importantly, we decode the plotted results according to water content of the respective hydrogels, which enables us to discuss and showcase outstanding contributions to the field. We limit ourselves to materials that have extensively been characterized regarding their stiffness, elasticity and fracture toughness. The fracture toughness is a particular important factor as it highlights the hydrogel's capacity to resist crack propagation during load-bearing applications. In the first part, we shape an overview of the available energy dissipation modes, which represent a key factor to access tough hydrogels. Many of the reported tough hydrogels have emerged through a clever combination of various dissipation modes, thus, an initial overview will facilitate the classification of tough hydrogels afterwards. The second and main part of this work deals with mechanical characterizations of tough hydrogels and the data it has produced. Individual analytical methods and parameters are briefly discussed, datasets are summarized and presented to elucidate trends and correlations among the various systems. Further to this, the literature data of tough hydrogels are categorized and compared to assess strengths and weaknesses of energy dissipation modes and hydrogel architectures. We then look at current applications of tough hydrogels, discuss comparative values in naturally occuring materials, and present individual examples of outstanding importance. In the last part, we briefly reflect upon the current distribution of mechanical properties of tough hydrogels and compare with existing materials with an eye on further potential applications that are currently being less explored.