BMo Expo is a cool plugin to create gallery items. If you are looking to add a fade effect on BMo Expo slider plugin, you can make a little change to the code to achieve this feature.

Plugin source: https://wordpress.org/plugins/bmo-expo/
Code suggested by: laCabriole, https://wordpress.org/support/profile/lacabriole

Solution:
In : wp-content/plugins/bmo-expo/js/jquery.bmoGallery.scrollGallery.js replace line 332 -339 with:
this.$bmo_the_gallery_images.css("opacity","0.0");
this.$bmo_the_gallery_images.animate({left:(-(index *
this.$bmo_the_gallery_image_area.width())) + 'px'}, "fast");
this.$bmo_the_gallery_images.animate({
opacity:'1'
}, "slow", function(){//complete
this.gallery.currentImg = index;
this.isAnimating = false;
this.setThumbs(index);
}.bind(this));
},