Fantastic was a British comic magazine published in the 1960's. It contained comic strips as well as black and white reprints of Marvel Comics stories. Here are a few X-Men related pinpus from the magazine. More pinups can be found in this Flickr gallery, courtesy of tinybatch:
While some of the images contain art from the comics, many of them appear to be original art produced for the magazine. Feel free to try to identify the artist of each piece.