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!
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.
Yokee - Karaoke to YouTube videos
Sing! Karaoke by Smule - Karaoke with your favorite celebrity singers
Acapella Maker - Acapella Maker is an intelligent application that allows you to make the desired video collage in an automated and easy way.
iSing Karaoke - iSing Karaoke is free to use the Karaoke app that offers free access to hundreds of songs.