Here are my results about Valentine/Electric hybrid ( Opponent XO Fox):
(Use against Valentine/Electric) Strong: Autumn; Earth; Electric; Lucky (Shamrock); Magic; Music; Rainbow; Royal; Zodiac
(Avoid using against Valentine/Electric) Weak: Valentine; Water
Neutrals with Valentine/Electric: Birthstone; Christmas; Dark; Egypt; Fairy; Fire; Halloween; Icecream; Legendary ( Crystal); Nature; Realm Rune; Service; Space ( Planet);Spooky; Spring; Treasure; Tree; Winter
Currently untested with: Bomb; Food; Skull
(All tests are done on IOS device, based only on Strong/ weak / neutral hits. Critical hits have not been taken into account. )