Blueprint Flipper is able to flip blueprints horizontally and vertically, has two buttons on the top of screen and hotkeys.
With a blueprint or blueprint book in hand, click on the associated button to flip the blueprint. Alternatively you can use the hotkeys:
Shift+z for Horizontal
Shift+x for Vertical
This version works with rail signals, train stations, Bob's Inserters and is updated for the 0.14 version of Factorio.
Credits to original authors: GopherAtl, Roktaal
0.1.7 Fixed Localization in config options.
0.1.8 Added Bob's Inserters Drop and Pickup