There are already many threads on this forum where you enter certain search terms to find websites that accept guest posts.
You can easily find these by just using the search function.
What I would add to the discussion is that you need to focus on niche relevance.
It's very easy to develop a shotgun mentality when it comes to guest posting.
The old idea of "the more the merrier" is very infectious.
And unfortunately, it's not going to help you all that much.
Niche relevance is going to help you.
It also helps when you're doing guest post outreach to clearly say what you will do.
You have to go above and beyond what other people doing similar outreach are prepared to offer.
One way that makes my own guest posting stand out is when I asked them for topic suggestions.
I publish a network of blogs and nothing pisses me off more than when somebody who is asking for a guest post dictates to me what I should talk about on my blogs.
Think about it, you're the one asking for a favor and you're the one dictating what I should and should not publish?
Do you see how ridiculous that is?
So the key is to askpeople based on what their content needs are.
This way you bring solid value to the table you are providing something that they don't have.
You are publishing around their needs and this makes you stand out from the rest of the people reaching out to them trying to get links through guest posts.
Do you see where I'm coming from?
Once they give you topic suggestions, come up with a way your website can benefit.
If it means publishing new content then do that.
By accommodating your guest post publishers you go a long way in getting more of your links out there.