Files with oom file extension can be found as swap files from old Shroom program.
OOM file extension - Shroom swap
What is oom file? How to open oom files?
File type specification:
The oom file extension was reported to have been used for some sort of Shroom swap file. Probably old or obsolete, no further information about this file type could be found.
This oom file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.