Physical goods are possessed. Intangibles are controlled. (Usually by getting your name added to the account or an agreement with the bank stating it will transfer according to the security agreement.)
For as-extracted collateral, timber to be cut, and fixtures, you file locally in the county where the property is located. UCC § 9-501(a)(1). (Because they are related to real estate)
Filing is generally required for everything except:
Some property like cars have titles. These goods often have separate perfection requirements, usually requiring the security interest to be listed on the title itself.
If someone purchases the collateral for value, the perfection will expire and be deemed to have never had existed as against the purchaser four months after the goods were purchased. UCC § 9-316(e).
The only way to perfect money (including gold) or a deposit account (e.g., a bank account) is to control it. UCC § 9-312(b). (But you can still attach to it.)
Delivery usually occurs when one acquires physical possession of a security certificate. UCC § 8-301.
Certificated securities can be controlled by delivery or by indorsement to the creditor or being registered in the name of the creditor. UCC § 8-106(a)–(b).
Uncertificated securities can be controlled by delivery or by having the issuer agree to comply with the creditor's instructions without the registered owner's further consent. UCC § 8-106(c).