I would consider work-life balance to be more of a problem than just being pestered to do unpaid overtime. For instance, companies which frown on taking time off or banking your leave to take one long vacation are fairly toxic IMO since they expect you to put the company first, even during your leisure. And that's ignoring places where it's expected that you be available on vacation, even if it's just to answer emails.

Some companies also require your work-life balance be broken down in order to advance. This is usually an unwritten requirement, and failure to participate makes you "not a team player," "a poor fit for the company," etc. I remember my father left a job because him going to see his father in the hospital after work instead of grabbing a beer (or a golf club) and shmoozing with the higher ups all but guaranteed he would never make partner at the firm. "Yeah, you might have kids to raise and your dad might be dying and all, but maybe join us instead so we can get to know you better and discuss your career ambitions" is one of the most disgusting attitudes I've ever heard, and yet many law firms still act like old boys' clubs, and a failure to suck up early on will impose a hard cap on your career. I would consider this to be a toxic workplace, both because of the "we're all family here (which means your family comes second)" attitude, and the implicit "if you bring in tons of business but don't fit in with our culture, you might as well start polishing your resume unless you're happy staying an associate."