This app was mentioned in 13 comments, with an average of 2.62 upvotes
There's an Android app that lets you see the world as if you were colorblind: https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads
Edit: and a Chrome extension: https://chrome.google.com/webstore/detail/chrome-daltonize/efeladnkafmoofnbagdbfaieabmejfcf
https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads
This app will let you observe how things appear with various types of colorblindness. It's a filter applied in real time on your camera.
I find this app helps explain it. Not perfectly accurate but gives a good understanding quickly and easily especially since it can use the camera and select the different types. https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads&hl=en
I got an app for my phone that simulates what a colorblind player would see: colorblind test.
Then I just point the phone's camera at my monitor to see how it would look for different types of colorblind players. Not sure how accurate it is but it seems like it gives a good idea.
There is an Android version too :
Colorblind Vision -- Realtime color blind vision – Use your camera to look through the eyes of the Colorblind. -- Colorblindness test – Take a classic Ishihara Test (dot test) to classify if you are colorblind. Build your own tests to say anything you want. Ever wanted to write a message that a colorblind person couldn't read? -- Learn about color blindness – Learn more about colorblindness, what it is, how it affects people, and the advantages and disadvantages of it. -- Extract colors - Pull out individual colors. Perfect for anyone who is colorblind. Can be used while playing board games to distinguish the pieces, or to help you tell if your clothes match.
And another one called ColorBlindness SimulateCorrect
If you want to see how colorblind people see (and have an Android device), install Colorblind Vision from the Play Store. This app allows you see the world through the phone camera as different types of color blind people would.
Disclaimer: I am not related in any way to this app or its author.
ColorOracle is a good one to test for colorblind players with screenshots on PC.
Colorblind Vision Free is a good android app to see a live simulation.
JAWS is the best screen reader to test with games.
A good thing to do would be to check out http://includification.com/ and check out the different levels of Mobility,Hearing,Vision,Cognitive and find ways to implement them without impeding on your game's concept.
As far as workflow it is hard to find one way that works best, but finding testers with disabilities and getting feedback early in development is important.
1 in 7 of the male population has some sort of color deficiency. 60% Neuromuscular disorders 60% people who report some hearing impairment. 25% of people have a visual impairment.
This is what I use: https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads
This app on android does pretty well
https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads
Is this the one you are talking about?
https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads
If so, I assume it is the "extract" mode that you find helpful?
Install this app to see like a colorblind person.
https://play.google.com/store/apps/details?id=com.givewaygames.colorblind_ads