I can't recommend you an oshi because that's a journey for yourself, but if you'd like a bit of direction I can try to provide that. If you're looking for something beyond the "big three", here are some smaller agencies to take a look at.
>V4Mirai
>PRISM
>Idol Corp
>Phase Connect
>Pixellink
A karaoke relay two days ago had a nice selection of talents from those agencies (pic related) so I recommend looking into their entries. They're only about 20 minutes long each, so a nice, quick demo for each.
There are also some great indies out there, but too many to list; the general is probably a better place to look.
