Several versions are available depending on your hardware needs:
On the left sidebar, refine your search: Windows 8.1 Lite Archive.org
Using unofficial operating systems from third-party repositories presents significant challenges: Windows 8.1 x64 & x86 (Official From Microsoft) (English) 19 Oct 2021 — Several versions are available depending on your hardware
To quantify why you would do this, let's look at a test system (Intel Atom N270, 1GB DDR2, 5400RPM HDD). Windows 8.1 Lite Archive.org