>>6708731BioSector's and BioMedia's collections are the most comprehensive out there.
https://biosector01.com/wiki/Gallery:Concept_Arthttp://biomediaproject.com/bmp/artwork/Here's further stuff that goes deeper, though some old links in the BZP topic don't work anymore.
http://www.bzpower.com/board/topic/12476-official-bionicle-concept-and-design/http://www.mproseimages.com/work-1/#/weg/http://www.alamy.com/stock-photo/bionicle.htmlThere are still a number of Bionicle CG images that, as far as I know, haven't been released in good quality, either in print or online. I was hoping Faber would manage to dig them all up and share them, but no such luck so far. For instance, the little promo booklet from 2008 that summarized the story up to that point had a couple Hordika renders I haven't seen anywhere else, but they're small and grainy.