You can purchase a Premium membership for only $35 per year, and this gives you access to download any or ALL of the over 400 add-ons developed for Xenforo 2.x. In addition, Premium members will get technical support. Once the Premium membership has expired you can continue to use the installed addons on your forum as long as you like.
On forums with many millions of posts, some add-ons (example: Convert image all) require you to temporarily change the max_execution_time to several minutes. For example you might change it to 300 seconds, or sometimes you will set to 600 seconds. After you run the add-on you can put the value back to the default of 30.