There's a light cyan blue and indigo-ish blue for BG-80. If you want durability, power, and grip, then BG-80 is your go-to string. You could also try some Ashaway string that have received good reviews, but I haven't tried any. I don't think many shops selling Yonex will string it with Ashaway.
BG65 and BG65P comes in Royal-blue. I've got BG65P in royal-blue on my New-colour AT700 and it looks very cool.
ah, isn't that like white AND blue ? Daisuke might be looking for a full-blue string.. but oh well, the colour doesnt matter much when it comes to playing..
Those blue strings i pictured are BG65Ti's,... BG80's come a little darker if i remember correctly and a re a little more vibrant blue if that makes sense. I would strongly recommend BG80's for colour and playability, but it's a prefernece thing too remember.
uhm i just want either that colour blue or a little darker blue, but is there a BG 66 high repulsion blue coloured string???