I found this breakdown of the "religious right" and "religious left" in politics from NPR pretty interesting. Basically, you don't hear much about the religious left because the left is more diverse and is harder to organize into some kind of political movement. Individuals are often motivated by their faith in their political priorities, but there are A) fewer voters whose religion plays a significant role on the left, and B) they are more diverse in opinion, making it hard to categorize them as a movement.
Even the coverage of the Christian Right is partly just inertia at this point. It's easier for reporters only loosely familiar with religion to have a unified block they can talk about. But as this election has shown, it's hardly a unified block anymore, and quite a few prominent conservative evangelicals have denounced Trump (not enough, in my opinion, but the division is there).
I also suspect, as I think I said in a post a few months back, there is less interest in the Christian Left to form a cohesive political voting block because that necessarily requires a kind of reduction of the issues. The success of the Christian Right (it could be argued) as a political block was their simplification of a broad conservative Christian message into "no abortion" and no "gay rights." That really did a disservice to conservative Christianity, often hurting their ability to be a force for good on other issues and allowing politicians rather than faith to direct their efforts.
Politics is important but it can be such a poison. Outrage and "speaking out" through voting or just on social media makes you feel like you are championing what you see as the public good. I think the danger can be (on the left or right) that it can siphon away your energy for doing what is definitely and obviously right: living in loving community: giving aid and comfort to the poor, the stranger, the broken who live near you all year long and not just on election day.
Anyway, I didn't mean to go on quite so long. Short version: while I want to continue to see Christians motivated by their faith to support candidates who will fight to end poverty and treat all people with the respect and dignity that they deserve as children of God, I would hate to see a Christian Left that mirrored the Christian Right. Because I think despite all the animosity and vitriol of the Culture Wars of the last few decades, the story of the political Christian Right is a deeply sad one.