There is a huge database of good songs which you can dedicate to your Mom depending on the occasion or event. You will have to dedicate a different song to your mother on mother’s day with the one you dedicated her on her birthday. You can choose from some famous songs like, Biggest Fan by the backstreet boys, mama by the spice girls, Momma by Chris Brown, Bob Seger or Hurricane Chris, I'll always love my mama by intruders.
Many musicians have dedicated songs to mothers in general. A few songs that are good to dedicate to your mother are "I'll Always Love My Mama" by The Intruders, "Mama" by Boys 2 Men, and "Thank You Mom" by Good Charlotte.