Relative popularity of different Arduino form factors?

[dlwilson1a]

Does anyone have any data, or at least an educated hunch, about which Arduino family board shapes are the most widely used? I have some ideas for a new shield and I want to design it to reach the maximum number of potential buyers.  Leaving aside the Uno, there is the Nano, the MKR, and the Micro, which all have a different physical form factor.

Are any of these clearly trending up or down, or already considered obsolete?

Bonus question: any information on the Adafruit Feather or the Teensy.

Thanks!

Moderator, please move this post if there is a more appropriate section.

[CrossRoads]

I'd say Rectangle, in general.

Are you looking to make one board with multiple parallel connector options so that it may be used with Uno, Nano, Promini, and others?
Will it accept 3.3V and 5V signals on all IO? Or maybe 2 versions, with different chipsets for each? Or maybe 3.3V to 5V level adapters for each IO? Have the IORef pin (on boards that have that) supply the reference level.

[dlwilson1a]

Are you looking to make one board with multiple parallel connector options so that it may be used with Uno, Nano, Promini, and others?

Thanks. For the time being, I'm not interested in making one size fit all. I'm trying to get a feel for which family to target first.

[hammy]

I'd say it depends on the shield type - possibly people with interest in shield type X tend to use firm factor Y.

If I was designing a shield I'd make it so the form factor is easily changed ( eg designed to fit a nano , but then easily adapted to fit the UNO , so you can easily make shields for either )