The Philistines descended from the Casluhim whom descended from Egypt. (Genesis 10:13)
Abraham and Abimelech's covenant
After making a covenant over a well dispute, Abimelech and Phicol returned to the land of the Philistines. Abraham sojourned there many days as well. (Genesis 21)
Israel vs Philistia. Israel lost greatly after bringing out the ark of the covenant
Israel encamped at Ebenezer and the Philistines encamped at Aphek for battle, and Israel was defeated, losing 4000 men. So they brought the ark of the covenant to the camp with Hophni and Phinehas. They shouted, scaring then steeling the Philistines, and lost greatly, losing 30,000 men. (1 Samuel 4)
Achish was forced by his people to send David back to Philistia, despite his good reputation with the king
The Philistines gathered all their forces at Aphek, by hundreds and thousands, while the Israelites were encamped by the spring in Jezreel. The lords of the Philistines asked why these Hebrews were here, and despite Achish insisting David's blamelessness to their cause, he had to send David back to Philistia early next morning, while the Philistines continued to Jezreel. (1 Samuel 29)
The Lord gave David victory against the Philistines after speaking the Davidic covenant
After receiving the Davidic covenant, the LORD gave victory to David wherever he went. David defeated the Philistines and subdued them, and David took Metheg-ammah out of their hands. (2 Samuel 8:1) King David dedicated the silver and gold from the nations he subdued, from Edom, Moab, the Ammonites, the Philistines, Amalek, and Hadadezer the son of Rehob, king of Zobah. (2 Samuel 8:11-12)
Four giant descendants slain during a series of wars between Israel and Philistia
Late in King David's reign, there was a series of wars between the Philistines and Israel in which David and his servants fell four descended from the giants in Gath. In the first, Ishbi-benob thought to kill David when he grew weary, but Abishai the son of Zeruiah killed the Philistine. That was the last time David's men allowed him to go out with them to battle, lest he quench the lamp of Israel. (2 Samuel 21:15-22)
The LORD worked a great victory against Philistia when Shammah, the son of Agee the Hararite took his stand in a lentil patch at Lehi
(This is part of a retrospective of the three, so it didn't necessarily occur at this point in the timeline.) The Philistines gathered together at Lehi, where there was a plot of ground full of lentils, and the men of Israel fled from the Philistines. But Shammah, the son of Agee the Hararite took his stand in the midst of the plot and defended it and struck down the Philistines and the LORD worked a great victory. (2 Samuel 23:11-12)