Definitely Doctor X... also perhaps Serei no Moribito.
Not sure how you'll like these (Romance) but:
-Misty (Can't remember but she is sure independent and powerful)
-Search:WWW (mostly cos of her career, is she intimidating??, I think she's independent and doesn't give an F, therefore is intimidating... romance plot is annoying...)
-Queen Seondeok (from what I remember she's a scary strategist)
-Hotel Del Luna (sorry, romance drama 100%... but you'll love her, she's the definition of INTIMIDATING!! Also she does have the clothes ahhhhhhhhhh)
-Graceful Family/ Crown Princess (typical evil family, innocent step-daughter justice etc. but they are independent and have some amazing moments... Intimidating... idk?? But they kick ass)
-Story of Ming Lan (she's not rlly intimidating, but strong and clever as hell, my fav. strong female lead ever... mostly she hides her ability at the beginning, so might need to wait a while)
*So couldn't rlly find what you were looking for really... mostly they're strong, but not to the point where people are quaking in their boots...
