ESPNU is dedicated to all things college sports. It has rights to cover games by several conferences, including SEC, ACC, Big Ten, Big 12, and Ivy League. It also broadcasts NHL on ESPN, NBA G League, Formula One, and more.
You can get up to 8 days of ESPNU for free by taking advantage of free trials offered by Hulu with Live TV, or DIRECTV.
ESPNU is also included in Sling TV + NFL Redzone Bundle (Sports Extra), Disney+, Hulu, and ESPN Unlimited bundle, and ESPN Unlimited, but they do not currently offer a free trial.