Other than Bolsonaro, who has been the most conservative Brazilian leaders?

[Suburbia]

?

[Make America Grumpy Again]

The ones during the military dictatorship

[President Johnson]

Michel Temer?

[buritobr]

Emperors Pedro I (1822-1831) and Pedro II (1840-1889)
All the presidents of the Old Republic (1889-1930)
Eurico Gaspar Dutra (1945-1950)
Café Filho (1954-1956)
The 5 generals who were presidents during the military dictatorship (1964-1985)
Fernando Collor de Melo (1990-1992)
Michel Temer (2016-2018)

[Suburbia]

Emperors Pedro I (1822-1831) and Pedro II (1840-1889)
All the presidents of the Old Republic (1889-1930)
Eurico Gaspar Dutra (1945-1950)
Café Filho (1954-1956)
The 5 generals who were presidents during the military dictatorship (1964-1985)
Fernando Collor de Melo (1990-1992)
Michel Temer (2016-2018)

Was Temer better than Bolsonaro? His wife is an attractive lady, I am surprised this didn't help his career.

Is there any Afro-Brazilian conservatives?

[buritobr]

Emperors Pedro I (1822-1831) and Pedro II (1840-1889)
All the presidents of the Old Republic (1889-1930)
Eurico Gaspar Dutra (1945-1950)
Café Filho (1954-1956)
The 5 generals who were presidents during the military dictatorship (1964-1985)
Fernando Collor de Melo (1990-1992)
Michel Temer (2016-2018)

Was Temer better than Bolsonaro? His wife is an attractive lady, I am surprised this didn't help his career.

Is there any Afro-Brazilian conservatives?

Temer was bad, but he was not as bad as Bolsonaro.
The beauty of first ladies is not an important issue.

Yes, there are many conservative Afro-Brazilian. The president of Fundação Palmares (a branch related to promote racial equality) under Bolsonaro's administration was a far-right Afro-Brazilian. Congressman Fernando Holiday is also a right-wing extremist.
Celso Pitta, mayor of São Paulo between 1996 and 2000, was not an extremist, but he was conservative.
The racial voting gap is not as big in Brazil as it is in the USA. Lula performed better in the group of blacks than in the group of whites, but this difference can be fulled explained by income.

[𝕭𝖆𝖕𝖙𝖎𝖘𝖙𝖆 𝕸𝖎𝖓𝖔𝖑𝖆]

Emperors Pedro I (1822-1831) and Pedro II (1840-1889)
All the presidents of the Old Republic (1889-1930)
Eurico Gaspar Dutra (1945-1950)
Café Filho (1954-1956)
The 5 generals who were presidents during the military dictatorship (1964-1985)
Fernando Collor de Melo (1990-1992)
Michel Temer (2016-2018)

Is Jânio Quadros typically considered a conservative in Brazil? I know he was elected with the support of the conservative parties but was more of a bizarre populist than anything.

[buritobr]

Jânio Quadros was endorsed by the conservative UDN, but he wasn't a member of this party. He was a populist conservative but he wasn't one of the most conservative Brazilian leaders. He won the election for president in 1960 and the leftist João Goulart won the election for vice president in the same year, because many people decided to vote for both, although they belonged to different tickets.
In his short term, Jânio Quadros conducted conservative domestic policies, but he was very progressive in foreign policy. He started a pro-Third World foreign policy and offered state honors to Che Guerara.