I think all the lore will fit in the main story, so I don't really intend to write anything else; however, my main story is divided in several (at least 3) arcs and each arc is constituted of one main plot and several subplots, so there is plenty of space for expanding on lore.
However, relatively early in the story (I think that will be chapter 4 and 5, not entirely decided yet), I have a subplot full of lore, and because it is well defined and can be pretty much read as a standalone, I will publish it as a sort of spinoff to avoid delaying the main plot too much. BUT I will reintroduce it in its right place in the story as soon as the first arc is finished.