phpBB is my personal favorite free software that uses the older forum/category layout, while newer layouts would have to be Flarum/Discourse for the thread/tag layouts.
For paid it would have to be WoltLab since it’s a free CMS+Paid forum/blog/gallery/calendar/file share. I’d love to say Invision but I feel as if it has gotten too bloated and price point is outside of many people’s budget, and vBulletin is just trash at this point.
Free: Forumotion or Proboards, they both have acp's that are easy to use even if you are a beginner (that's a big thing with me) and they have good support on their support forums and I've not had trouble with my forum being down
Paid: No idea
Here are some popular options for free and paid forum software:
Free forum software:
PHPBB: PHPBB is a popular open-source forum software that is widely used by many websites. It offers a wide range of features and customization options, and it is regularly updated and supported by a large community of developers.
Simple Machines Forum (SMF): SMF is another open-source forum software that is popular for its simplicity and ease of use. It offers a range of features and customization options, and it is supported by a large community of users and developers.
MyBB: MyBB is a free, open-source forum software that is known for its user-friendly interface and extensive customization options. It offers a range of features and is regularly updated and supported by a large community of users and developers.
FluxBB: FluxBB is a lightweight, open-source forum software that is designed to be fast and easy to use. It offers a range of features and customization options, and it is supported by a large community of users and developers.
Paid forum software:
XenForo: XenForo is a paid forum software that is known for its advanced features and customization options. It offers a range of features, including social integration, mobile support, and user management tools, and it is supported by a team of developers.
vBulletin: vBulletin is a paid forum software that is known for its extensive features and customization options. It offers a range of features, including social integration, mobile support, and user management tools, and it is supported by a team of developers.
Invision Community: Invision Community is a paid forum software that is known for its advanced features and user-friendly interface. It offers a range of features, including social integration, mobile support, and user management tools, and it is supported by a team of developers.
These are just a few examples of the many options that are available for free and paid forum software. It is important to research and compare different options to find the best fit for your needs.