I don't believe there is any official large lineage, unless you've homebrewed it in, but small should probably be an option
#Elemental Scion creature size
cobalt walrus
lost frigate
Centaurs are large - Midgard Lineages and Heritages
narrow hemlock
I think what No One was trying to say here is that there is not a core lineage that is large (which is correct). The Midgard Lineages and Heritages are supplemental (and may be even considered lower than a lineage from a published supplemental book, like the Labyrinth Worldbook, because they are sort of like polished blog material). The L&H and ML&H supplements are not core to the system. Celeste has said that weird size lineages shouldn't be baked into the core rules (#1472518163492245595 message) which is why you don't see support for tiny or large sized lineages in the core books - Player's Guide 1 & Player's Guide 2.
woven lagoon
Yeah, basically, if your GM is fine with you being large, you can be, but it's not a "core" option.
plush saffron
While true about the Centaur, the bigger point is that since Elemental Scions can be any lineage if it's created, having the choice between small and medium should have been baked in on the lineage itself.
lost frigate
Unless there is a really good lore reason for them to only be medium creatures.
narrow hemlock
While true about the Centaur, the bigger point is that since Elemental Scions ca...
Yeah. I agree that from the beginning Elemental Scions should have had both small and medium as an option. Just wanted to make sure people know why the other sizes won't be included.
woven lagoon
they are taller than humans, so maybe it's just that the elemental power makes them bigger