Typeform-like online form builders without steps? [migrated]

I want to develop a form for data collection of real-time events: users can input the time, location, event type and description using the form.

Currently I'm trying to make a mock-up of the form. However, all the online form builders I can find are designed for surveys and questionnaires, and so they're always designed in a linear fashion. It doesn't suit my purpose because the user should not be restricted to fill in each piece of information in sequence (in fact, users might not even have some pieces of information before the others, so it doesn't make sense in the first place).

So a typical Typeform design would be:

[Start] -> [Time] -> [Location] -> [Event Type] -> [Description] -> [Submit]

while what I want to achieve is

[Start] -> [Main Form]
(in any order)
[Main Form] -> [Time] -> [Main Form]
[Main Form] -> [Location] -> [Main Form]
[Main Form] -> [Event Type] -> [Main Form]
[Main Form] -> [Description] -> [Main Form]
(after all mandated fields are filled in)
[Landing Page] -> [Submit]

Are there any online tools that can mock up such forms with good-looking designs like Typeform? I don't want to make the actual form yet; I'm mostly trying to evaluate the design to see if it'd work as the real deal.