PhotoGrid - Picsart removed a lot of grid options from its collage feature, and limited the amount of pictures to 10. While this app is inferior to Picsarts quality, it lets you choose max 15 pictures and has numerous layouts.
Sing! Karaoke by Smule - Karaoke with your favorite celebrity singers
Acapella from PicPlayPost - Acapella from PicPlayPost developed by Mixcord Inc.
iSing Karaoke - iSing Karaoke is free to use the Karaoke app that offers free access to hundreds of songs.
Brillar - Bring glitters, stars and sparkles to your videos and photos.
SingPlay - SingPlay Karaoke Your MP3s developed and published by NexStreaming Corp.