The U.S. House of Representatives consists of 238 Republicans, 197 Democrats, and 6 vacant seats. The House, among other things, has the power to initiate bills and impeach an official.
I’ve listed women of color first, followed by white women, and just to be detail complete, included a less detailed list of male democrats in tossup districts at the very end. If you’re interested in supporting more women of color in states marked safe for Democrats or in non-Congressional races, I recommend resources such as Black Women in Politics.
The U.S. Senate consists of 51 Republicans and 49 Democrats (which includes 2 liberal independents). The Vice President (Mike Pence, Republican) can cast tie breaking votes, tipping the Senate further Republican.
For the Nov 6, 2018 mid-term elections there are 26 Democratic controlled seats on the line, and 9 Republican. The Democrats have more potential for loss than gain.
Democrat control of the Senate will effectively block Trump’s major initiatives for the next 2 years. It will also set up the next President to have a clear path towards undoing damage and effecting greater change. To win, Democrats need an overall net gain of 2 seats. The chances of this are slim, but possible with enough action from people like us.