Yes, there are lots now! There are some good ones, but some are definitely way pricier than I think they should be. With Next.js, you can even use Wordpress as a cms to back a static blog (https://github.com/vercel/next.js/tree/canary/examples/cms-w...)

Just a few off the top of my head:

- https://graphcms.com - https://prismic.io - https://www.sanity.io - https://www.datocms.com/ - https://www.cosmicjs.com/

More at the top of this Next.js docs page:

https://nextjs.org/docs/basic-features/data-fetching#simple-...

I've spent quite a bit of time playing with Nextjs, so if you have more specific questions feel free to let me know.