In general, OmniFocus is not used for reference items. Instead, any task manager is best suited for action. Once something is done, we mark the corresponding task as complete, and move on. However, it is also useful to have our tools and materials nearby.
Sometimes that could be as simple as adding the URL or link to something in a task’s note field. For example, here is a link to a URL using Hook:
However, sometimes I can have a whole set of files that I just want handy. Though they are not currently tied to a task, they may be relevant to the project. For these, I’ve created a “Reference” tag which has been set On Hold:
Notice that I’ve placed them all in a group, which itself is tagged with the “Reference” tag.
Closing all note fields makes for a nice aesthetic:
There are certainly other ways to manage references, but I’ve found this to be quite handy.