Washingtonian Magazine has an article “50 Great Places to Work in Washington”(March 2017), link here.
The list online isn’t quite the same as in print. For example, online we see American Immigration Lawyers, which is an interesting choice given the times (and the people helping immigrants need as much legal help sometimes as the immigrants themselves).
The last comprises a variety of small companies, some with fewer than 25 associates. Many are partially “employee owned” – wonder if that means you get paid in stock. Many offer all kinds of generous benefits and paid, gender-neutral family leave. All would be LGBTQ friendly, probably (although one of them is mostly working moms).
They are in a variety of businesses (one even sells cars); some are Beltway-bandit software companies. Some are in healthcare.
Many are located just outside the Beltway (Rockville MD is popular).