Periodically, I come across an object that has fields I can access in a Flow or perhaps a SOQL query but that are not listed in the Object Manager (either in Lightning or Classic). Is there a standard way to discover all of these fields? At the moment, I've resorted to using the REST API and making a describe call to an Object, which does return these "hidden" fields.
For example, we use Price Books within our Org. I can query the PricebookEntryId field on a QuoteLineItem even though it is not listed under "Fields & Relationships" within the Object Manager for "Quote Line Item".
Other than resorting to making REST API calls, or perhaps downloading the WSDL schema, how would one normally "discover" these fields?
Bonus Round
Similarly, but slightly different, is getting a list of fields where the field name and the relationship name differ. (ex: PricebookEntryId and PricebookEntry, or Product2Id and Product2.)