I created these tools in desktop years ago and they worked up until yesterday and then they just disappeared in desktop? I can see them in Pro, but not desktop? Any reasons as to why this happened? I made no changes to the tools, but I do believe I viewed them in Pro at one point.
Using a custom tool, model or script in a newer version of ArcGIS automatically converts it to the newer version. For example, using a script tool in ArcGIS Pro would remove the tool’s backward compatibility with ArcMap or an earlier version of ArcGIS Desktop. A previous thread discusses potential workarounds for this (in case you didn’t make a backup), and focuses on the actual toolbox: Opening ArcToolbox Tools in previous versions of ArcMap?.