If you use Endomondo.com to track your unicycle rides, there are two challenges for 2019.

Max distance ridden in 2019:
http://www.endomondo.com/challenges/39277095

Max time in the saddle for 2019:
http://www.endomondo.com/challenges/39277087

There is a challenge for time because the unicycles with larger wheels have an unfair advantage in the distance challenge. Also, the trials riders can participate in the time challenge.

You will have to track your rides as "Cycling Sport”. (for historical reasons…)