When 0.1" is too big, and JST PH's too chunky, this ultra-slim 1.25mm connector cable is a reliable alternative. These are 1.25mm pitch but have a nice clicky connection.
This cable is handy and not too long, 20cm in fact. The friction lock makes easy-breezy connections whenever you need light and small connectivity.
Note that this cable is 1:N type wiring, which means that on a 4-pin cable, for example, the first pin on one connector will go to pin 4 on the other side, and vice-versa.