Most of the General insurance companies offers health / mediclaim policies. Also today Life insurance company have got daily cash benefit health policies, which is certainly different from general insurers medicalim policy.
Further every policy have some unique feature. only we have to pick-up the best that well suits our need and premium band.
Presently 22 general insurance cos. are there in indian market. out of which only 2 are stand alone haelth insurer.
Most important is that you have to look at the TPA service provider of the insurer as these days mostly claims are approved on cashless basis and are dealt directly by the TPAs, off-course the policy terms and conditions are the primary basis on which the claims are considered. So you have to focus on product, TPa and the insurer all together.
U may find out with Star Health Allied Insurance co,
Tata Aig General Ins. co., National Insurance company to name a few.