Belarus: I could see CPB taking over when Lukashenko isn't in charge anymore.
Burkina Faso: Their prime-minister seems to be a communist. Hopefully this means working towards a socialist state.
Cyprus: AKEL is one of the main opposition parties in Cyprus and their candidate for presidency went to the runoff election this year.
Greece: KKE is one of the main opposition parties and they keep growing.
Haiti: There are some revolutionary organisations involved in the protests against the government, maybe they'll succeed.
Swaziland: The CPS is the main opposition to the king's rule.
Taiwan: through reunification with PRC.
What others seem likely to you?
EDIT: I remembered South Africa is a candidate as well, the EFF is getting stronger
Not possible. There aren’t any significant real communist parties in Russia
CPRF is literally the second largest party after the ruling one
Controlled opposition. Plus, it's a shell of a proper communist party.
Doesn't do agitprop, nor community work like it should
the KPRF is full of old bureaucrats who would surprise me if they had a communist bone in their body. Perhaps if the upper leadership is purged, but that is unlikely.
There is a nonzero chance of a socialist movement being truly revived, Russia cannot hide from its past for long.