Japan
The Japanese Communist Party has 270,000 members as of 2020 and 4,483,411 votes in the 2019 Upper House elections, their record being 8,195,078 votes in the 1998 Upper House elections.
Source: https://en.wikipedia.org/wiki/Japanese_Communist_Party
Russia
The Communist Party of the Russian Federation has 162,173 members as of 2019 and received 8,659,206 votes in the 2018 Presidential Election. Their record was 24,211,686 votes in the 1996 election.
Source: https://en.wikipedia.org/wiki/Communist_Party_of_the_Russian_Federation
South Africa
The South African Communist Party has 220,000 members as of 2015 and participates in the ruling coalition.
Source: https://en.wikipedia.org/wiki/South_African_Communist_Party
Iraq
Unknown membership amounts, received 1,500,862 votes in the 2018 elections.
Source: https://en.wikipedia.org/wiki/Iraqi_Communist_Party
Brazil
The Communist Party of Brazil has 396,542 members as of 2019 and received 1,673,190 votes in the 2018 general election, their record being 12,561,716 votes in the 2010 elections.
Source: https://en.wikipedia.org/wiki/Communist_Party_of_Brazil
Bezotcovschina wrote
That's what fits in my definition of "Left Conservative".