Here are a few measures from four pop songs from the early 2010's that your students can attempt to sightread, all in bass clef.
Note: Most are actually female singers - it's just for bass clef practice.
#1 - You Belong to Me (first line of song)
#2 - Gangnam Style (“Hey, sexy lady”)
#3 - Call Me Maybe (part of chorus)
#4 - I Need a Doctor (first line of song)