For social class, you find below codes in Stata, R, SPSS and SAS for constructing my class scheme (discussed here in 2006 and 2023). To write your own code, refer to the Excel sheets below, which show how occupations are assigned to classes.
For Stata, Ben Jann (University of Bern) has written the Stata module “crosswalk” which creates my class scheme based on ISCO (“ssc install crosswalk” & “help crosswalk”). For R, the same is possible using the DIGCLASS package, developed by the EU-JRC DIGCLASS team.
For occupations’ earning potential OEP (discussed here), you can download the Excel files that assign OEP values to occupations here for ISCO-88 and ISCO-08 (at the 1- to 4-digit levels). Besides the common scale, these files also show the specific OEP values for Germany, Sweden, Switzerland, the UK and the US.
For Stata, the Stata module “crosswalk” creates OEP values based on ISCO. For R, the DIGCLASS package does the same, constructing OEP values for ISCO occupations.
Occupations (ISCO) into classes
Excel for occupations measured with ISCO-08 (4-digits)
Excel for occupations measured with ISCO-08 (2-digits)
Excel for occupations measured with ISCO-88 (4-digits)
Excel for occupations mesured with ISCO-88 (2-digits)
European Social Survey (ESS)
For a summary of my class schema and its coding in the ESS, see pdf 
ESS 2002-2006 (rounds 1 to 3) in Stata
ESS 2008-2010 (rounds 4 and 5) in Stata
ESS 2012-2020 (rounds 6 to 10) in Stata
ESS 2002-2010 (rounds 1 to 5) in R or in SPSS
ESS 2012-2023 (rounds 6 to 11) in R or in SPSS
International Social Survey Programme (ISSP) + MOSAiCH
ISSP 1987-2013 (+ cumulated dataset on Social Inequalities) in Stata with a table for variable names
ISSP 2014-2017 in Stata
ISSP 2010, 2011 in SPSS
MOSAiCH-ISSP 2017 in Stata (for Switzerland)
MOSAiCH-ISSP 2019 in Stata (for Switzerland)
MOSAiCH-ISSP 2022 in R (for Switzerland)
German Socio-Economic Panel (SOEP)
SOEP (CNEF equivalent file, all availables waves) in Stata
Swiss Household Panel (SHP)
SHP 1999 up to latest wave in Stata
SHP 1999 up to latest wave in SPSS
SHP 1999 up to latest wave in SAS
Swiss Election Studies (SELECTS)
SELECTS 2019 in Stata, R or SPSS
SELECTS 2015 in Stata, R or SPSS
SELECTS 2011 in SPSS
SELECTS 2007 in SPSS
SELECTS 2003 in SPSS
SELECTS 1999 in SPSS
SELECTS 1995 in SPSS
Luxembourg Income Study (LIS)
Create a hierarchical 4-class variable for many countries and years in R