I don´t think someone here have any bootable floppy disk images with games for this emulator.
The floppy disk format between the IBM JX (3.5") and IBM PCjr (5.25") is different and not compatible.
So you can not use IBM PCjr disk images.
Unfortunately, a ROM cartridge support is missing on Takeda´s emulator.
The IBM JX has 2 cartridge slots (A/B) like the IBM PCjr.
Some commercial games for the IBM PCjr are available as cartridges (River Raid, PitFall II, CrossFire, ...) which are already dumped.
The IBM JX has a I/O port for the cassette recorder to use tape images which is missing on Takeda´s emulator too.
Not to mention the harddisk support for the later IBM JX models.