which caching plugin is best to use

Hi @manoman,

which caching plugin is best to use with this wpForo plugin?

You can use the WP Rocket or WP Super Cache cache plugins with wpForo plugin. You just need to exclude your forum home page from your cache plugin. Almost all cache plugins should have an option to exclude pages from the caching process. This is very important.
More info about wpForo and Cache Plugins you can found here: https://wpforo.com/community/faq/wpforo-and-cache-plugins/#post-37150

Below is provided the related topics, please check it out: https://wpforo.com/community/?wpfin=tag&wpfs=cache

And what other plugins will help optimize the forum?

wpForo works fine with minimize and optimize plugins. For example in the wpForo.com we activated Autoptimize and as you can see all JS and CSS files are minimized and optimized without any issue. Just press F12 and check it in browser console.

No doubt no plugin is better than WP Rocket for clearing Cache, But yes WP Rocket is a paid plugin so for more options you can check out this detailed guide about the best WordPress caching plugins 2020.

https://www.reviewsed.com/best-wordpress-caching-plugins/