The older Sigma 85 f1.4 EX has a good reputation, but I would expect some focus issues. You might want to check it out.
I have a copy of the Tamron 85 f.1.8 which I think is really good. It is sharp, has beautiful bokeh and I love how its pictures looks. I think it has much of the same qualities as the 85LII, but sharper edges, and that says a lot. It is also weather sealed and reasonably sized.
it has IS, but for some reason I find it to blur the images taken at 1/125 - 1/180 sec, which is a much used aperture speed for me indoors, so I opted to turn of IS in such instances. AF isn’t as good as Canon 85 f1.4, but it is fairly good I think.
Unless you really need f1.4, I think you should be very happy with the Tamron. It is a significant step up from Canon 85 f1.8, especially at large apertures. I like its clarity and color.
edit: I almost sold the Tamron due to the IS issues I mentioned, but after reviewing the keepers I got from it, I couldn’t. The pictures looked too darn good. I have most of the Canon L lenses up to 200mm, both EF and RF, so I think that says a lot.