Here are some common ones I’ve come across:
“Hey hey, ho ho, ___ has got to go!”
“what do we want? fair treatment! When do we want it? Now!”
“No Justice, no peace! No justice, no peace!”
Another tip, if you’re walking a picket line…it can get really exhausting to chant for hours, and people will lose their voices. Try buying whistles. People can blow the whistles while they walk the line, so they’re still making lots of noise, but not getting a sore throat. Drums or buckets to bang on do the same thing, and make it festive rather than dreary.