These are small softwares that I made. Use them at your own risk.
I have only Sharp IS01, IS03, and ASUS ME173X. So I don't know whether they work on other android phones and tablets.
All of them are for android 1.6 and up. Source codes are also available.
If you don't know what dingux is, you don't need to read here:-)
A two-column style file manager. You can Copy, Move, Delete, Rename files, and Create Directory on dingux.
A simple text file viewer. It can display Japanese, and if you put an appropriate UTF-8 font file, it may display various languages, I think.
A Game Boy emulator "gambatte", compiled for dingux. I modified it a little to use on A320: fitting to a QVGA size screen, simplification of a sound filter.