From low end to high end :

Futaba 9351
Ace Hobby DS-1015
Sanwa ERG VX or VZ*
KO Propo PDS-2368*
KO Propo PDS-2386 ---> stronger than 2368 but slower
Hitec HS-5955TG*
JR 9100T
JR DS8711*

*I'm using those servos for throttle & steering in my cars.