The Peterloo protest was hugely influential in giving ordinary people the vote, as well as leading to the rise of the Chartist movement, trade unions, and the establishment of The Manchester Guardian in 1821.“
The Chartist movement wasn't particularly strong in Manchester and the Guardian was a paper set up by mill owners and it famously opposed child labour laws, well they would wouldn't they.
The Luddites were also not a Manchester movement, being Nottinghamshire and West Riding based
A few other things to mention, Mill Workers anti slavery protest,1862,
Not sure what is meant by protest, but this wasn't just in Manchseter, it involved all Lancashire, and especially Cheshire. Stalybridge (Cheshire) was probably most involved and affected by the manufacturing distress at this time.