MX schemes are for ministries (well, most).
From what I know, we can separate them into different tiers if we are looking at salary for fresh grads:
some stat boards like NHB, NAC,
SSC,
NLB get lesser.
followed by ministries like
MOH,
MOE and MEWR.
economist schemes, MOF, MHA,
MAS,
EDB, IE singapore etc get more.
SAF,
RSAF, navy, police and other uniformed stat boards/organisations get more.
administrative service scheme get the most.