Do people use running Parachute and Agility Ladder for martial arts training or it is not something useful?
Martial arts drills involve a large set of aspects of a human body. It may be difficult to find all the ways that can help your body to adapt to these drills.
Anything and everything that tests your endurance, strength and agility will be useful for the training.
Agility laders, although can be used, will not be of any much utility. This is because the drills and work outs of a martial artist test, increase and build up your body for further adaptation at every stage. However, the effectiveness of agility ladders can be easily forgotten in this case; Since there are other more fruitful ways of building up agility and endurance.
Running parachutes are definitely used in all sorts of sports today including martial arts (Of course depends on what art you are learning). That being said, it again may not be as useful as some other drills.
Certain points to be noted :
Some martial arts like Muay Thai, where stamina plays an exceptional role, are definitely an exception.
These tools do provide a healthy amount of utility but at a marginal expense of a lot of time that could be invested in better ways of improvisation.
This answer is completely based on my experience in Krav Maga and Kung Fu.
Hope this helps! :)