how do I access the sd card to see what's saved on it?
Sorry you had to resort to resetting your phone just to get rid of some ringtones.
To see what's on the SD card (and on the phone's internal memory) you can install any number of File Managers from the Google Play Store, or you can just use the one already included on your phone - the 'My Files' app (just look in your Apps Drawer).
When it opens, by default it shows the phone's internal memory (/storage/sdcard0) - just press the 'up arrow' icon in the upper right hand corner, or press the 'left arrow' icon in the upper left corner - either one takes you up one level to the /storage view, where you can select the SD card (/extSdCard).
From there you can roam around the contents of your SD card.
BTW, ringtones normally get downloaded to /storage/sdcard0/Ringtones
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