If these are Saved Searches, go to your Saved Searches page and unsubscribe from updates from those searches you no longer wish to receive. Click the "More actions" option and use the "stop email alerts" option if it is available.
https://www.ebay.com/mye/myebay/savedsearches
You may also want to check your Communication Preferences page and uncheck any options you do not want.
https://commspreferences.ebay.com/commsprefs
