Is it permissible to give a portion of profit or anything else as an appreciation for the help of colleagues, knowing that they do not ask for anything and help for the sake of Allah?

It is forbidden to give a percentage of profit or gifts to employees if that leads to favoritism towards the giver of the gift and prioritizing him over someone more deserving in the work, because it is considered prohibited bribery. However, if these gifts do not lead to favoritism, then there is no harm in them.