Understanding protein expression across tissues and organisms is crucial for elucidating functional similarities and differences in physiological processes, which is essential for selecting the appropriate model organism in biomedical studies. We present a comprehensive analysis of protein repertoires across 25 tissues in Xenopus frogs, using advanced quantitative mass spectrometry to measure the levels of over 15,000 proteins. By comparing these profiles, we reveal tissue-specific expression patterns and identify conserved proteins shared across diverse organs. We explore evolutionary strategies of ubiquitous and tissue-specific proteins and discuss the search for 'missing' proteins that have vanished in human samples but appear in frogs.