In my opinion, it's pretty much like common sense that it can be quite effective to not only train bilateral (Squats, Bench Press, Bent over Rows, Deadlifts) but also unilateral (Split Squats, DB Bench Press, DB Rows) from time to time, for various reasons. One of them being to prevent imbalances.
However, now I'm wondering: For pretty much every bilateral exercise there is I can easily think of a unilateral alternative, except for the Deadlift. The Deadlift (or Romanian Deadlifts, if you want to hit the hamstrings harder), to me seems to be a one of a kind exercise where I can't really think of a substitution.
Are Dumbbell Deadlifts a thing? If yes, are they worth trying? Or am I better off training Leg Curls unilateral to hit the Hamstrings, even though they might not activate them to such a big extend as the Deadlift?