All the people who were doing that are now pushing RCV or other election reforms that would make it realistic for third parties to be able to get all the way to winning. The third-party people who are running in FPTP elections are, almost universally, either attention-seekers or deliberate spoiler candidates. Bernie Sanders, when he was running, joined up with the Democrats instead of running as a spoiler candidate, because he's making an earnest attempt at making things better.
It doesn't really matter now because we've slipped one rung down the civilizational Maslow pyramid now, and are in for a fight to preserve the right in any capacity to elect who we want in power. But, whenever we make it back out to the other side of that, it'd be nice to remember to reconfigure the system so third parties can actually win, first, and then run third party candidates after that, not the other way around.
Bernie Sanders did that, and it did great. It wasn't enough to win, partly because the Democrats fucked him.
At this point, you'll have to contend with massive social-media operations which are working against and shaping the narratives that most of the country use as a substitute for news, to understand what's happening in the world. I think the time to be able to do it has passed, for a little while, without on-the-ground anti-electoral organizing on a massive scale.
See who you can find in your area. It's about to get real, I think.