Can I create custom forms without having to specify an effective date?
Yes. Previously, any custom form created was of a "History Grid" type form. This means that all forms captured need to have an effective date that is unique, and is used to store information that has a history record- i.e. the pay rate screen is an example of a history type form, where you have multiple records being effective date driven, and always only one active record.
Another option has been added to create a form that is of "Library" type (can also be referred to as "Lists"). This form type does not require a unique effective date. An example of this type of form is the assets screen - an employee can have multiple active assets at the same time.
Navigate > Configuration > Basic Settings > Custom Screens & Fields > Custom Form Configuration