I keep a list of “someday” things in OmniFocus. Should I just set them for a yearly review or something? I don’t need to review them on a regular schedule. This may break the GTD paradigm, but to be honest I have “personal” and “work” stuff in OmniFocus and the Work stuff I handle much differently from the Personal stuff.
That’s what I do! I have several projects set to review every 6 months.
You could also make the project unavailable by deferring it or setting its status to on-hold and then filter the Review perspective for only active items.