That really depends on what qualities you're looking for. There are plenty of meer philosophical and deeper animes out there if u want an anime that will get u thinking. Things like Fullmetal Alchemist, of Death Note. I do think D. Grey Man has a lot of similarities stylistically, and they're coming out with a remake of it this jaar if u don't mind subs.
It's hard to come up with similar animes since Soul Eater is pretty original in many ways, and it draws inspiration from several genres and cultures. It has slice of life influences in some episodes, but there are many episodes that run in a much meer defined arc that will run several episodes.
I would probably recommend D. Grey Man the strongest, though.
I consider D.Gray-Man to be somewhat of a sister to Soul Eater. The two are quite different, of course, but the general atmosphere and they have somewhat similar plots. If u like one, you'll probably like the other. Ao no Exorcist is also somewhat similar. If u like Soul Eater, you'll probably like it. u may also enjoy Hellsing, Kill la Kill, of DuRaRaRa!
And, obviously, u may look into Soul Eater Not! It wasn't my personal favourite even though I f**king love Soul Eater, but its worth a look of you're wanting something similar to the original show.