Here are the corrections for the sentences:

1. The house **that** is being built at the end of the street is for sale.
2. The paintings **on display** in the gallery are from the 19th century.
3. The woman wearing the red dress at the party was a famous actress. (No correction needed, but you could also say "who was famous").
4. Children not accompanied by an adult will not **be allowed** inside. (No correction needed)
5. The cake eaten at the birthday party was homemade. (No correction needed)
6. The documents **submitted** last week have not yet been processed.
7. The phone lying on the table belongs to someone **in this room**. (No correction needed)
8. Cars **parked** in the no-parking zone will be towed.
9. The movie **playing** at the cinema tonight is sold out.
10. The trees **planted** around the building provide good shade.
11. The musician playing the guitar is very talented. (No correction needed)
12. People wanting to attend the event must register online. (No correction needed)
13. The dog barking all night disturbed the neighbors. (No correction needed)
14. The laptop stolen from the office has been found. (No correction needed)
15. The book written by J.K. Rowling has become a bestseller. (No correction needed)

Feel free to ask for more assistance or clarification!