Even if you find a traditional publisher who will look at unagented manuscript/proposals/queries, you're still immensely better off with an agent. Just because a publisher looks at such things does not mean they actually buy from them. Such things are often for goodwill with writers, but are not taken seriously.
I remember one very large publisher that was/is well known for looking at unagented material, but they actually bought something this way only once in more than ten years.
"Filtered through an agent" is how publishing works. It saves editors an immense amount of time, and assures them that most of what comes in is close to, or above, professional level, even if it's something they don't want.
If you can find a good agent willing to represent your book, what makes you think an editor will want it, either? It's always tougher to sell directly to an editor than it is to find an agent willing to represent your book.