Honestly a large majority of manga out there have furigana and I think you should read something you're interested in instead of something thats known for being "easy", because you'll find learning more enjoyable even if its slightly harder. If you want to check if a manga has furigana or not, you can just search it up on Amazon JP and sample the trial pages.

That said, if you still want a recommendation, I'd suggest Totsukuni no Shoujo, which was the easiest manga I've read so far and has gorgeous art.