Hmm. I don’t know too much about their distinguishing traits, but I’ll attempt to reach back years into my mind and see what I can pull out.
One thing I recall about them is their immense size, with Manda being about 100m long. Then there is the issue of their durability. They were capable of tanking massive amounts of damage due to their scales, making them immune to attacks of A rank and below, and if I remember correctly, they could shed their skin and tank even higher levels of damage. Besides that, there is the ability to burrow underground and sense opponents through vibrations.
What I remember most about them is their versatility in the ninjutsu techniques shown by Orochimaru. Using them, he could break his body into a myriad of snakes, with his real self hidden within one as a means of escape, and things like shadow snake hands, where a bunch of small snakes are released from the sleeves. He even had them burrow through the ground to attack opponents from a distance
In terms of strengths, I’d say their defensive capabilities are a big one, as I touched on above, but a potential drawback for them could be their eyesight and their need to taste the air to effectively 'see' or sense the world around them