Looking for Companies that Focus on Mostly DSA and System Design

I have 3 YOE as a software developer, and my current tech stack does not have that many opportunities. I'm looking for an exhaustive list of companies that I can apply to that ask only DSA and System Design. Almost any company that you guys reply are appreciated, and I'll compile a list and post it here.

Also, how do I find such companies on my own? None of the job platforms seem to have a filter to search for such companies.