We are a team of two, both do design, code and database. Here i am talking about a desktop application, usually we develop custom database applications for small-medium businesses. We actually follow agile but a bit our own way. This is how we start when a new project comes.

1. We receive the requirements but do not start anything until an informal meeting in which we work out the all requirements(modules/features) 70% each.
2. Then I do the front-end design(forms/windows) and my friend design the database, No back-end logic till now.
3. Once all the forms and database designs are ready we send it for customer evaluation. a) For the designs that are approved, I start to write classes and back-end logic (Requirements freezes here) b) He work improving/changing the designs the customer rejected or asked for a change. (In this phase we welcome new requirements, not requirements change. The one client freezed will not change as i have started to work on its back end.)
4. Step 3 repeats until the (b) is eliminated. The Project is Ready!

I'm alone with myself :)

Anyway I started using react storybook to develop react components in isolation, it's really cool.

https://github.com/kadirahq/react-storybook

I am the lead designer and engineer. With my app it was design first completely and then develop because it was an in house project. Websites I do more of a mixed process, coding along with designs, which I pass to clients and then adjust based on feedback.

Well, I am a BE developer. We have FE guy and designer. As soon new projects kicks in, we all look at it and then we have 2 work-flows:

1) The design has been shipped with product specifications, which means that I can start working on some BE logic for which I don't need FE dev, and he/she can do her part of the job. When she is finish, all or part by part, I just pass BE logic in dummy-hardcoded FE data.

2) The design has not been shipped, and when all is done from designer, we proceed as in first work-flow. We don't start the project before the at least 80% of design has been approved. If some extra design changes are needed, they are handled in the process, and we must be always ready for that.

If only world would be so ideal you just described. What if I tell you that back-end starts doing his job blindly, front-end has nothing to do (well, he/they can learn another framework, may be that's the reason we have a lot of them?), design agency sent you only 1st desctop version of index page without any instructions, UI kits and without an information that Grid layout spec will be available in 5 years may be but not now. Next month you receive new information, something changed and you have no idea how to structure your frontend. One more month later your $primary-color becomes secondary or even worse. Later you see in design there is something you have never seen before and didn't evaluated it, in some cases you have no idea how to do that.

Finally after a year you received some parts of UI kit and instructions, you can now see a big picture, but, when you think that you know need to refactor whole architecture, you just close your laptop, smile and leave office, mute your phone, take a random bus into unknown direction and just enjoying your life.

I'm a freelancer so I don't know. personally i prefer the en.wikipedia.org/wiki/Design-driven_development with dummy data.

and her approach https://www.youtube.com/watch?v=7OSkB4BCx00 seams to be pretty solid to me :)

As a developer I know that we need to stay "agile", but getting a mockup first than iterating over different parts with the designers and after taking out the "scope breaking" features showing the customer feedback speeds up your process and reduces overhead :)