Let's take a look at the models of some of the new Crafting Motifs or Outfit Styles that might be coming to ESO in Q4 2020. These Styles were found in the game files with the release of the Update 6.1.0 and Stonethorn DLC on PTS. They are Ancestral Akaviri Style, Ancestral Barbaric Style and Ancestral Breton Style.
First, here are the UI icons of the style materials that will likely be used for crafting these Motifs.
The models found for these Styles are heads, chests, shoulders, elbows, waists, tassets and knees with some exceptions for certain armor variants.
As with the other, already released Ancestral Styles, the new ones seem to be a rework of the corresponding base game Motifs. As such, they look very similar to their base game counterparts but are more detailed and have a few minor changes.
It's probably safe to assume that these new Styles will be obtainable through the Antiquities system in the same way as the Ancestral Altmer, Ancestral Nord and Ancestral Orc Styles.
By the way, the Ancestral Breton style can already be seen in-game on PTS as it looks like Gwendis wears medium armor in this style (sans a helmet) in Stonethorn DLC and Count Verandis Ravenwatch wears a light variant (no head piece either) in the Markarth DLC prologue quest.
Lastly, the chest models for the previously datamined Dark Passions Regalia and Subterrane Excavator Costumes have also been found and are showcased below, as well.
If you want to discuss this datamine with other ESO players, you can join the ESO Model Viewer Discord server.
Keep in mind that these models were found in the game files and these Styles are not officially confirmed. As such, they might change significantly on release or might never be released at all.