I've been doing a lot more loaded carries in my own training lately. I find that they have a profound effect on stability/rigidity which helps my performance on the big lifts.
They also are very effective for body composition, both muscle growth and fat loss.
At the moment my main carries are farmer's walk and Zercher carries with a strongman log (much more challenging than it looks). The later is probably the most demanding core exercise I've done!!!
This morning I also experimented with backward farmer's walk. Challenging hip stability movement and worked even better than regular farmer's walk to improve upper back position.
In my next workout I will have overhead carries with the strongman log.