There's a long-term visit pass (LTVP), which is what I hold. LTVP holders may be given a pre-approved letter of consent (PLOC) which allows them to seek employment basically as freely as a PR (I also hold a PLOC).
An LTVP/LTVP+ holder who is married to a Singaporean or PR.
An unmarried child (under 21 years old) of a Singaporean or PR, who holds an LTVP.https://www.mom.gov.sg/passes-and-permits/letter-of-consent/...