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.
KaraFun - KaraFun is the best online karaoke. Over 35,000 karaoke songs, with studio quality, at home or on the go. Regular updates. Free demo!
Acapella from PicPlayPost - Acapella from PicPlayPost developed by Mixcord Inc.
Yokee - Karaoke to YouTube videos
Brillar - Bring glitters, stars and sparkles to your videos and photos.
Sing! Karaoke by Smule - Karaoke with your favorite celebrity singers