llist = [{'a':'foo', 'b':'bar', 'c':1}, {'a':'foo', 'b':'bar', 'c':2}, {'a':'foo', 'b':'bar', 'c':3}, {'a':'hui', 'b':'pizda', 'c':1}, {'a':'hui', 'b':'pizda', 'c':2}]
lnew = {}
for n in llist:
    for k, v in n.items():
        if k in lnew:
            lnew[k].add(v)
        else:
            lnew[k] = {v}
print(lnew)