I would say... 😂

Empathy - for your users and coworkers. What are they trying to do? How do they feel? What's motivating them right now? What's worrying them? A powerful question about your coworkers is to consider if you know what they are being measured on - what are their goals?

Communication - being able to clearly express ideas, concerns and advice.

Presentation - you need to be able to speak to a room. Doesn't have to mean full public speaking at conferences etc, but you do need to be able to handle speaking to a group like a meeting (and be able to read the room and know what level of detail to be supplying and what issues to focus on more). Almost everyone claims to be afraid of speaking, but in reality most people haven't invested any time in learning how to do it; nor have they ever spoken about a topic they are passionate about. Many people first do public speaking in situations they didn't choose and may also be highly emotional - doing a report in class at school about something that bores you; or speaking at a wedding or funeral. These things do not have much in common with standing up to pitch an idea at work that you've researched and really care about. Most people can do a decent job of that!

Time and task management - this includes self-awareness about how you do your best work, and how to arrange a schedule that maximises the time you spend in that zone. Also an understanding of prioritisation, estimation and so on. It's not glamorous but it will impact you every day of your career.

Business sense - perhaps not a soft skill per se. But having some idea of the strategy, direction and current state of your organisation - even if it's only the broad strokes. It's amazing how many devs blunder along having no idea at all about this - eg. pitching high-risk moon-shot solutions for something when the company has a reduced capacity for risk, or the reverse of being super conservative when the company has a higher appetite for bigger risks and returns. Just because you aren't calling the shots doesn't mean you should be ignorant of the shots being called.

Another important one is consistently informing managers, mentors etc in a timely manner if e.g. you get stuck (mentor) before it's too long, or if you're not confident you can deliver at the time previously communicated (manager).

If you don't do that, time is wasted and deadlines are missed. If you "usually" do it (like 75% of the time), that's not enough for your manager to trust that she doesn't need to ask for your status every day, just to be sure..

The most important soft skill is the Ability to Accept and Learn From Criticism. Then you need the willingness to help and ask help from your co workers. These 2 are enough. All other soft skills will automatically come. Like Communication skills etc.