In no particular order...

Torm(and by extension the always described as "probably equal to that of a Trom" Lobar) are sapient. Seemingly in the way of wolves in that it says they that they lack language, but it's not like your normal WoT human would be able to check for telepathy.

Interestingly the phrasing would suggest this is at least somewhat suspected IU, but... It's the Seachan we're talking about.

Then there is(in one of the surprisingly few times OP mechanics even comes up) where it says that the Keeping weaving is ether a time slow or stop weave(the Aes Sedai don't yet know IU).

Straight up confirmation of channelers having resistance to disease(minor, but as the fairly commonly held by the fans belief was before based on little but an off hand comment by Nynaeve... Still nice).

In the entry on Far Madding while talking about the Guardian it says "Also as with a stedding, anything channeled against the city simply melted away at the edge of the active area; even balefire directed at Far Madding dispersed on hitting that border" which is likely the closest we're ever going to get to evidence as to whether or not balefire is an actual "thing" made by a weave... Not sure it's really enough to say, but it's likely the closest we're ever going to get.

As I don't really care about the life story of random Aes Sedai #359... it's pretty slim otherwise.

...Oh, Aiel Laws. Most of note personally is simply that they consider failing show up for trail or meet a sentence to make one sub-human... One kind of wonders how that is going to effect their new role as the world police. lol