My love of sunburst mirrors and convex mirrors goes back to studying Van Eyck's Arnolfini Wedding. I loved this reflected wink to the viewer, which reveals the artist himself, as well as the opportunity Van Eyck took to beat his chest about his artistic prowess, all the while recording somebody else's marriage.
Then I read Hockney's Secret Knowledge and learned the importance of optics, lenses and mirrors in these artists work. It remains one of my favourite art books. The small selection shown is from 1stDibs, each stunning - I couldn't pick a favourite.