After the visa has expired, can a foreigner work in Poland while awaiting a decision on a residence permit?

If on the day of submitting the application you could work on the basis of a registered declaration on entrusting work to a foreigner (declarations are issued from 01/01/2018) or work permit at the employer you work with in the same position, and you applied for a residence permit being legally in Poland and there are no formal defects - you can work during the procedure for granting a residence permit. If you do not meet the above conditions, you can work as long as you have a work permit or a registered declaration on entrusting work to a foreigner.