What are your favorite niche/obscure exercises?

oliveoil

Exercises that I love and never see anybody do at the gym:

Here is my list:

Skin the cat
https://youtu.be/QHnpUcVwZOk?si=jAF97PWS2QzaX_8H
One of the best calisthenic exercises, amazing for shoulder mobility and strength. When holding the bottom position (aka German Hang), it will stretch your shoulders, chest, back and biceps; it feels incredibly relieving.
Zercher Squats
https://www.youtube.com/shorts/i5jOlUpm64c
Try them if you are a tall person. I have never felt more comfortable doing weighted squats than with this variation. It biases the weight more to the front, which in my opinion is better because getting good at this exercise will carry over to more common strength movements, especially in martial arts.
Zottman Curls
https://www.youtube.com/shorts/fMMv0LfzYMk
It's simply a bicep curl where you pronate your grip before the eccentric phase. For some reason, it feels much smoother and comfortable in my elbows to do it this way. Definitely try them if you have elbow pain.
Neck exercises
https://www.youtube.com/watch?v=WtKdTeMZx5E&t=388s
To be honest, it's the most overlooked muscle group, but training your neck has a very good ROI for what it takes. If you don't regularly train your neck, start doing it during the rest between your sets. Having a strong neck not only makes you look like a Chad, it could save your life in a fight or car accident.
Handstands
https://www.youtube.com/watch?v=hRmZu6UdPCk
You need to do handstands more often. You need to do handstands with different variations. You need to do more calisthenic movements if you aren't already. Calisthenics is peaty.
RTO dips and pushups
https://www.youtube.com/watch?v=m4PClV2vYvQ
If you have never tried this, this probably doesn't look that difficult to you. But trust me, it's one of the hardest push up and dip variations to exist. It puts a massive amount of tension in your biceps.

I agree about neck’s being incredibly neglected, even these pro body builders rarely touch their neck, it’s so odd seeing these incredibly built physiques with little pencil necks.

Not to mention neck training is probably the #1 thing you can do to improve your looks as a man.

3D

@oliveoil JM Press, but on the Smith machine: https://www.youtube.com/watch?v=Tih5iHyELsE

Also growing your neck too big might induce sleep apnea, I would avoid training neck directly if you hit it with other compound exercises anyways.

metabolicmilk

I'll add some KB exercises like
KB Halos
Kettlebell Sots Press
Kettlebell Bottoms-Up Press
Kettlebell Windmill
Kettlebell Figure 8
Kettlebell Turkish Get-Up (TGU)
Kettlebell Dead Stop Clean
Kettlebell Curtsy Lunge with Press
Kettlebell Tactical Lunge
Kettlebell Half Snatch
Kettlebell Suitcase Carry
Kettlebell Russian Twist
Kettlebell Rotational Swing
Kettlebell Side Lunge with Rotation
Kettlebell Around the Body Pass
Kettlebell Woodchopper

cokefiend

Olympic lifts

Sprinting

Plyometrics