There are none that I'm aware of, and after the SEO2 fiasco, I don't think that I'll rely on any addons for SEO again (luckily I didn't change titles or extensively use it to change URLs).
What I used it for can be accomplished with custom fields and template modifications.
Custom field placement would make SEO additions a lot easier though! With that, there wouldn't be a complex template edit to hide the fields. Then, you can edit in an og:title and custom meta title apart from the thread title. Additionally, you could at least define an og:image URL with a custom field, until attachments can be used. Also, you can use Schema markup as desired.
I don't understand how everyone here is saying XF's seo is miraculously good out of the box.
You can count even on this forum the dozens of vbulletin boards that have been killed by switching to XF, mostly due to the way vbulletin boards were clearly processed in a special way by google, whereas xf boards are not.
JUst to name a few of what I think are problems
Direct links to post on the homepage, leading to pages like myspost/#32 beeing indexed in google ; your surfers end up in the middle of a thread, don't undestand what's going on, and simply hit "back".
Multiple URLs for the same page ( don't tell me about canonical - google mostly ignores it, at best it post process them if you're lucky ) like /post/ /post/#1, /latest, and so on. You end up with an horrible mix of indexed urls in google.
Since XF1 they refuse to simply add the forum name in the url (board.com/forumname/thread), something every other board engine does, which gives them a major seo boost.
A boatload of URLs that google should not index at all (members, quicksearch, news feed) even on this very forum the webmaster had to "tweak" his robots.txt to blacklist a couple of XF's most prominent pages - so they are not indexed. A tweak customers don't have out of the box.
the sitemap, generated every 24h (sic), doesn't even contain the multiple pages of threads.
I could go on.
Imho, it needs major rework. Every successful board running XF I see has made major tweaks to the engine, especially to the way the pages are displayed to unregistered users (like googlebot ).