ContractAddressZeroable is the implementation of the trait Zeroable for the ContractAddress type. It is required to check whether a value of t:ContractAddress is zero or not.
The contract_address_const! it's a function that allows instantiating constant contract address values.
Into<T> is a trait used for conversion between types. If there is an implementation of Into<T,S> for the types T and S, you can convert T into S.
TryInto<T> is a trait used for conversion between types.If there is an implementation of TryInto<T,S> for the types T and S, you can convert T into S.
get_caller_address() is a function that returns the address of the caller of the contract. It can be used to identify the caller of a contract function.
get_contract_address() is a function that returns the address of the current contract. It can be used to obtain the address of the contract being executed.
This is not an exhaustive list, but it covers some of the commonly used types and traits in contract development. For more details, refer to the official documentation and explore the available libraries and frameworks.