Project -> Project Packager generates a zipfile of everything Altium thinks should be in the project. Copy that file to a new directory, unzip it and use it for a while. (You'll also see if you've done something odd and used files from other directories by mistake).
After a while, delete the original directory.
Well, that's how I tend to do it.
(but yes, all those files you listed are either old versions (which I like to keep for a long time!), or uninteresting (like schdocpreview)