Depending on the hierarchy of items of your scene, even searching in the Hierarchy window can be a nightmare.
If that helps you, here a little script I've written. It always starts the search by the Universe. Give it the name you're looking for, not case sensitive. 
Tested on P11 and P12

import poser

def find_obj(obj_src, obj_name):
    if not obj_src:
        return None
    if obj_name.lower() in obj_src.Name().lower():
        return obj_src
    for child in obj_src.Children() or []:
        if obj_name.lower() in child.Name().lower():
            return child
    for child in obj_src.Children() or []:
        check = find_obj(child, obj_name)
        if check:
            return check

    return None

scene = poser.Scene()
try: universe = scene.Actors()[0]
except: universe = None
if universe:
    dlg = poser.DialogTextEntry(False, "Find what?")
    if dlg.Show():
        what = dlg.Text()
       
        res = find_obj(universe, what)
        if not res:
            poser.DialogSimple.MessageBox("'%s' not found" % what)
        else:
            scene.SelectActor(res)

𝒫𝒽𝓎𝓁

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