Update: apparently, now, the SpecNext has added ULA Plus compatibility, but not licensed the trademark so they don't say so.

Still, this is good news. There are already enhanced games that use it, originally for emulators and later for machines upgraded with a physical ULA Plus chip...

https://www.sellmyretro.com/offer/details/slam-ula-plus-repl...

... and now you'll be able to play them on actual hardware.

Examples of such games and how they look: https://sites.google.com/site/ulaplus/