There are a lot of mods for LA already, and hopefully will be more after 1.4005 release, which should be in december, 2017. You can find some already (all of them are 3rd party, except the OST, that is officially made by us):
http://www.moddb.com/mods/lost-alpha/addons
We plan to make official addons, like weapons pack, different hands models, textures addons, more playable areas etc etc.
(for these, no dl link yet
)