Gamma Professional - close to natural Gut string feel, very good ball feel but easier lost tension
Tecnifibre X-One Biphase : very good ball feel and good tension keeping
ISOSPEED Professional : similar the above feel and it had tech for arm protection.
If you want to have more power and keep similar feel, ISOSPEED AXON Multi is a good choice, there is a monofilament core in the middle and covered by many layer of Liquid Wax. You can get good ball feel and the string can provide power.