You could try asking on the Sketch Plugins Developer Forum https://sketchplugins.com

Plugins are written in JavaScript, so any JS developer should be able to build a plugin. What makes it tricky is that the public API (which is well documented https://developer.sketch.com/reference/api/) isn't complete. Many features can only be accessed through an undocumented private API. This is where someone with plugin development experience will have an advantage, but that person might be harder to find. If your plugin will have a complex UI or needs to extend the Sketch interface, things get trickier still, and familiarity with Objective-C might be useful.

Yes. It's the feature I like most about Craft. But I stopped using Craft because of problems with Sketch updates, and I thought I'd write my own... Craft puts the same image in every symbol which isn't what I was after. My plugin gives you a random image for each selected symbol or shape. Unlike Craft, my version doesn't allow you to target specific layers in the symbol, instead it just swaps the largest image in the symbol.

If you're running version 1.1.1 of the plugin and you're wondering why it doesn't do anything... Something went wrong with the publishing process. Sorry about that! Please update to version 1.1.2. All fixed now :)

I found the documentation on Framer really helpful. Particularly the programming guide: https://framer.com/getstarted/guides/programming/ and the code guide: https://framer.com/getstarted/guides/code/ And Mike Johnson's videos on https://www.framercasts.com/ are great.

A Medium article that walks you through building a prototype of a simple design would be awesome.

Nice! Be cool to have the videos for doing all these things in Pixelmator Pro or Affinity Photo. That way I don't need to fork out for Photoshop as I hardly ever use it.

Pixelmator Pro or Affinity Photo? Which is better?

Awesome! I've been waiting for this for a long, long time.

There was an issue with the beta when copying artboards between documents where library symbols were converted into local symbols. I heard the guys at Sketch were on to it. Can anyone at Sketch give us an update on when we might see a fix for this?

Done

I'll see if I can add one to to GitHub page