Arguably, the humble Deadlift, is one of the most important lifts you can do. It is unequaled when it comes to teaching how to interact with the ground and developing systemic tension.
Most lifters are familiar with the Conventional Deadlift or the Sumo Deadlift. Both are very popular, and effective, in developing strength and power. The setup and execution for both are relatively simple to learn and "expertise" can be developed in both in a relatively short period of time.
There are several other Deadlift variations that, while just as or possibly more effective than the Conventional or Sumo Deadlift, don't get as much appreciation.
The Hack Squat (or Deadlift Behind the Legs) is an excellent technique that challenges the athlete in ways that the Conventional and Sumo Deadlift can't. This variation reinforces a strong, tight starting and ending position, as well as requiring a near vertical drive out of and into the starting position. Deviations in technique or bar path are instantly apparent and this makes this technique almost self correcting. I did say almost, didn't I?
The Jefferson or Health Lift is the Granddaddy of Deadlifts (pictured below). This is one of my favorite variations of the Deadlift because of the required attention to detail on the setup, as well as their being a "right side" and "left side". This is tremendously disconcerting the first couple times you do this lift, but once you've ironed out the kinks in your stance, it will be a staple in your Deadlift training toolbox.
NOTE: every single time I do the Jefferson Lift I get a host of comments about how dangerous it is for your "nether regions". I've been teaching this Deadlift Variation for several decades and I've NEVER had anyone come close to hurting themselves. Of course, if you were training T-Rex to Jefferson Lift... then all bets are off!