FPbase is a community editable, searchable database of fluorescent proteins.
Using advanced search, one can search for a FP by name, or by any other property – sequence, Ex, Em, QY, EC, photostability, brightness, organism, year of publication (a total of 20 paramters). Through the “explore” menu there is an interactive chart (what used to be the FPvis website) and a spectra viewer. You can read more about it at the Addgene blog.
The second site is the Fluorescent Biosensor database which allows you to browse or search for biosensors of any class (e.g. cell cycle, pH, metabolites, ion, kinases, proteases, lipids etc…). The database provides, the name, type of biosensor (e.g. ratiometric, FRET, translocation or intensity) and the references.