Useful ipad apps for students in mainstream education

Hello,

I'm a KS4 and 5 teacher in Northern Ireland and we have received some funding that has allowed us to get iPads for our students to use.  I would like to get some apps put on these to help our students with autism in areas like organisation (mind maps, etc), timers, emotional regulation and anxiety management, or any apps that would be useful to assist in day to day school life.  If anyone could suggest some apps that they have used that have been successful or useful for students aged 14-18 I would be very grateful.  Thanks!