I've just installed a new add-on which shows the "Best Posts" on the forum, and on a per thread basis, using the number of likes or positive ratings each post has received.
*"In a nutshell, Best Posts makes your forum useful to a wider audience by making your best content more easily accessible.
One of the largest issues with the standard forum format compared to Reddit-like upvoting is that posts that aren't on the first and last pages of a thread tend to get overlooked. Not an issue for your regular users who are primarily interested in the latest posts, but what about new users?
Best Posts has you covered: the global and per-forum modes allow users to see at a glance the most interesting posts your site has to offer, while the per-thread mode injects new life into your megathreads, release threads, build log threads, etc., where the content readers want is hidden among pages of comments."*
You'll find the link to click in the top navigation bar:
Enjoy