• SwiftLaTeX (https://github.com/SwiftLaTeX/SwiftLaTeX / https://www.swiftlatex.com / https://doi.org/10.1145/3209280.3209522 — the cool demo that used to be on their site seems to be gone, but see HN discussion: https://news.ycombinator.com/item?id=21710105)
• Texpad https://www.texpad.com/
• BaKoMa TeX (http://www.bakoma-tex.com/) — its eponymous author Basil K. Malyshev passed away recently, but the product and page still exists for now
• VorTeX (see Pehong Chen's PhD thesis from 1988 https://www2.eecs.berkeley.edu/Pubs/TechRpts/1988/CSD-88-436... — it actually discusses the issues of quiescence, etc).