Be careful not to box yourself into a concrete search term for your topic. Think of synonyms for your subject - broader terms, related terms, and narrower terms. Using this strategy will guarantee a wider selection of materials. Be aware, too, that some search terms may be uncomfortable to think or say out loud - but could yield possible results.
As the term implies, LGBTQ+ is an umbrella term for multiple gender and sexual identities. The Human Rights Campaign offers a fairly comprehensive glossary - many terms can be used to conduct searches in the CRC's catalog.
Possible search terms: homosexuality, transgender people, children of gay parents, lesbians, gender identity, asexual, intersex