The first one that's right around the corner is in Honduras. While I almost stopped following this election because it seemed like a lost cause, it has now become the most promising.

Xiomara Castro is the wife of former President Manuel Zelaya, who was deposed in a military coup in 2009. Her getting elected would be an enormous boon to the region. Not to mention a continuation of the region turning to the left.
Remember all of those migrant caravans? Honduras is where they were coming from, and to give you an example of why, consider this story from today.

Honduran authorities on Thursday arrested presidential candidate Santos Rodriguez over accusations of money laundering related to drug-trafficking and homicide, including the murder of a DEA informant.

His arrest comes less than a month ahead of presidential elections in which the main candidates all face accusations of either corruption or drug trafficking.

Outgoing President Juan Orlando Hernandez has himself been accused of drug-trafficking, while his brother Tony Hernandez was in March sentenced to life in prison in New York for the same crime.

The concern with Honduras is the chances of the totally corrupt political leadership rigging the election like they did in 2017, and then crushing the protestors with police violence.

The news isn't so good for Chile, which will have an election at the end of the month.

The leftwing candidate, former student leader Gabriel Boric hasn't so much fallen in the polls, as he's fallen behind Jose Antonio Kast. The problem is the implosion of the center-right candidate Sichel, who's followers has moved to the far-right, Bolsonaro-like Kast, a supporter of the dictator Augusto Pinochet.
This is not good. But it's too early to despair because neither candidate is likely to get a majority, so a run-off will almost certainly happen in December. I've seen no polling for the 2nd round run-off.
Recall the Chilean election from earlier this year for rewriting the neoliberal constitution. The progressives surprised the pollsters and crushed the conservatives in that election.

In the spring of 2022, Colombia will hold its own election and leftist Gustavo Petro is said to be leading by a lot, but I've been unable to track down the polling to back that up.
Brazil's 2022 election is further away, but Lula is dominating the polls and I just don't see that changing.