This app was mentioned in 3 comments, with an average of 1.33 upvotes
i use this App/Widget. i place these slider Widgets on left screen so i can see/adjust volumes for Media, Alarms, Ringtone and it's just a quick swipe away. you can also add Notification but i don't because it's same as Ringtone. if you use Nova Launcher with "Subgrid Positioning" enabled, you can re-size the widgets to be long and thin. i love it -
Volume Control Widget by Adam Wolfe Gordon
https://play.google.com/store/apps/details?id=ca.xvx.volume&hl=en
Volume Control Widget by Adam Wolfe Gordon https://play.google.com/store/apps/details?id=ca.xvx.volume