This app was mentioned in 1 comment, with an average of 1.00 upvote
If you have an android device there is this timer:
https://play.google.com/store/apps/details?id=affinitegames.warzonetimer&hl=en&referrer=utm_source%3Dgoogle%26utm_medium%3Dorganic%26utm_term%3Dandroid+warzone+timer&pcampaignid=APPU_1_FAKlVpLgCojUjwO8_52YDA