Potatoes
Chop a few slices of raw potato and put them in the dish. The potato will absorb the excessive salt from the dish. Let them remain in the dish for about 15 minutes and discard them before serving.

Flour dough
Make small balls of flour dough and put them in the curry. Keep cooking for around 10-15 minutes and the balls will soak excess salt from the dish. Take them out before serving.

Yoghurt
Add 1-2 tablespoon of yoghurt in your curry to neutralise the salt.

Tomato
you can add finely chopped tomatoes or tomato puree and cook for few more minutes.

Onion
Add raw onion to the curry for a few minutes. This will balance the excess salt in the dish.

Vinegar and sugar
use a tsp of white vinegar with a tsp of sugar in the dish.

Milk
Coconut milk can be added to gravies to neutralise the excess salt and balance the flavours although this will alter the flavour