Kindred:
Death's averted/damage prevented with R;
highest crit with E;
distance traversed with Q;
number of jungle camps stolen;
number of champions fates sealed (marked and killed within 30 seconds);
highest total damage from wolf during a single W cast;
champion kills from wolfs W while outside of lamb's range;
number of successful tower dives survived due to R;
number of times you killed the enemy jungler in a 1v1 (no assist) while they were marked
(fun) number of times wolf circled lamb;
And I could probably think of many more. Arguably some of them would require a bit of effort to be tracked accurately, but I'd say none of them would be crazy hard to achieve.