Here are some (in) appropriate ringtones for the thirteenth day of the Omer:

1. Thirteen by Johnny Cash

2. Thirteen by Garbage

3. 13 by Megadeth, the 13th track from the album TH1RT3EN

4. Thirteen by Big Star 

5. Thirteen by The Antlers

6. Thirteen by Venom

7. 13 by The Brian Jonestown Massacre

8. Lucky 13 by Smashing Pumpkins

There are a bunch more “Thirteen” ringtones (already formatted as ringtones) on Audiko