I often filter out .wm
Other people may have more suggestions.

I think it's safer to put a full stop before the extensions. You never know what files you may accidentally filter out by not doing so. eg: words like -> midway, middle, wave, timid, arm, elektra, & other names, etc.

If possible, try searching at different times of day. People come & go all the time from the network & you will find different results over a 24 hr period ... and over a 7 day or 14 day period, etc.