As so many botbr noobs asks where midi files can be created/edited, perhaps a list like this can be useful:
desktop operating systems - exports/imports .mid files:
- Aria Maestosa
- musescore
- rosegarden
- lmms
- ardour
- cubase
- fl studio
- REAPER
- digital performer
- Sekaiju
- JAZZ
- Domino (en translated version)
- Anvil Studio
android:
- perfect piano (saves midi format, has a virtual piano keyboard, midi/usb controllers can be used)
- Maestro (Sheet music composer, saves midi format)
misc:
- munt uses different instruments, but allows you to capture a midi file from a midi controller connected to your computer
- midicsv (converts midi to csv and back, command-line based)