Krdytkyu

We see lots of people lose some organ of their body in accidents. What kind of past life bad Karma causes this?
Which Purana has commented on such bad karmas.
Also is there any Purana/s that states remedies for past life bad karmas?

Vishnu Smriti and Satatapa Smriti are two such scriptures that extensively deal with this topic. These texts link various sins committed in previous lives with the diseases/bodily deformities that one is supposed to get in the current life.

Quoting from Vishnu Smriti XLV:

1. Now after having undergone the torments inflicted in the hells, and having passed through the animal bodies, the sinners are born as human
   beings with (the following) marks (indicating their crime):


2. A criminal in the highest degree shall have leprosy;


3. A killer of a Brâhmana, pulmonary consumption;


4. A drinker of spirits, black teeth;


5. A stealer of gold (belonging to a Brâhmana), deformed nails;


6. A violator of his spiritual teacher's bed, a disease of the skin;


7. A calumniator, a stinking nose;


8. A malignant informer, stinking breath;


9. 
   A stealer of grain, a limb too little;


10. One who steals by mixing (i.e. by taking good grain and replacing the same amount of bad grain in its stead), a limb too much;


11. A stealer of food, dyspepsia;


12. A stealer of words[1], dumbness


13. A stealer of clothes, white leprosy;


14. A stealer of horses, lameness;


15. One who pronounces an execration against a god or a Brâhmana, dumbness;


16. A poisoner, a stammering tongue;


17. An incendiary, madness;


18. One disobedient to a Guru (father), the falling sickness;


19. The killer of a cow, blindness;


20. The stealer of a lamp, the same;


21. One who has extinguished a lamp, blindness with one eye;


22. A seller of tin, chowries, or lead, is born a dyer of cloth;


23. A seller of (horses or other) animals whose foot is not cloven, is born a hunter;


24. One who eats the food of a person born from adulterous intercourse[1], is born as a man who suffers his mouth to be abused;


25. A thief (of other property than gold), is born a bard;


26. A usurer becomes epileptic;


27. One who eats dainties alone, shall have rheumatics;


28. The breaker of a convention, a bald head;

32. Thus, according to their particular acts, are men born, marked by evil signs, sick, blind, humpbacked, halting, one-eyed;

33. Others as dwarfs, or deaf, or dumb, feeble-bodied (eunuchs, whitlows, and others). Therefore must penances be performed by all
means.

A similar list is also found in the Satatapa Smriti.

Also is there any Purana/s that states remedies for past life bad
karmas?

Yes, the remedial measures are also given along with in the scriptures. They involve fasting (like Samtapana, Chandrayana, Tapta Kirrikha etc) or ritual/worship or in some cases charity too. Most of the remedies (except the charity ones) are too cumbersome and people of today's time will find them very difficult to perform.

Some verses (which include remedies too) from Satatapa Smriti's Chapter 4 are as follows:

The pilferer of brass is born with tawny-coloured eyes. Fasting on an
Ekadasi day and bedecking a good Brahmana with ornaments, he should
present unto him one hundred Palas of brass. (4)

A person pilfering pearls is born with tawny coloured hairs.
Fasting, he should give away a hundred pearls according to proper
regulations, (5)

A person, stealing tin is born suffering from eye diseases. Fasting
for a day, he should give away one hundred Palas of tin. (6)

A person pilfering lead is born suffering from head-diseases.
Fasting for a day, he should give away one Dhenu weight of clarified
butter according to the proper regulations. (7)

A person stealing milk will be born as a diabetic patient. He should
duly give, unto a Brahmana, milk one Dhenu in weight. (8)

By stealing milk curd a person is born insane. For purification, curd,
one Dhenu in weight, should be given by him unto a Vipra. (9)

A stealer of honey is born being subject to eye-diseases. After
fasting, he should give, unto a twice-born person, honey, one Dhenu in
weight. (10) A stealer of sugarcane-preparation [becomes subject] to
Gulma [chronic enlargement of the liver or spleen]. For the expiation
of that sin, molasses, one Dhenu in weight, should be presented by
him.