The best alternatives to lightgallery are Pixave, imagetasks, and BetterViewer. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of lightgallery?
.Tech Domains — Get a .tech domain for your startup, year 1 on the house.
BetterViewer was designed as a replacement for the image viewing mode built into Firefox and Chrome-based web browsers. With BetterViewer you can use various keyboard shortcuts to quickly pan, zoom images, edit and a lot more!