It seems that both OpenBSD [1] and NetBSD [2] still support i386, for example here [3] you can find the image for a USB stick.

I expect at least the base system (including X) to work without big issues (if your hardware is supported), for extra packages you may need a bit of luck.

[1] https://www.openbsd.org/plat.html

[2] https://wiki.netbsd.org/ports/

[3] https://wiki.netbsd.org/ports/i386/