Well the first techno artists and music of their's that come to mind are:

perfume:
dream fighter, fushizen na girl, night flight

aira mitsuki:
barbie barbie, wonder touch, china discotia

Sawa:
swimming dancing, merry go round, many colours,

Mizca:
dameyo, robotics, kira kira

MEG:
Kittenish, secret adventure

capsule:
hello, love or lies

also Boa's song Lazer is also a bit technoish