If I file motion to close estate/ what happens to undistributed assets theyre mine

What is the name of your state? Texas

If I file or have someone file a motion to get estate closed,
what happens to all assets not distributed by executor who refuses to close estate. Can I still claim them? And how? He is in possession of a large some of money also not distributed to me. I have no idea what happened to it..

The point of filing the motion is to also clear up any unfinished business that the executor has not taken care of. Therefore, you and your attorney can bring up the subject of the unclaimed assets and anything else you think hasn't been taken care of, and the executor will have to explain/account for his actions at the probate hearings.