It is possible to add custom search fields to item search. (see bug See https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=13823 ) You can even use wildcard characters with such a search. It would be important that those fields would be made visible in the search results, as well. I suppose a common use case is to add public and nonpublic notes to the custom search fields. However, those are not visible at the search results, and thus it's difficult to utilize the search results, and process the results further. I assume there will be some other use cases than note fields, as well. At least add those public and nonpublic note fields, but even better solution would be if you could customize which fields are shown in the results.