Raid Battle RewardsAfter defeating any type of Raid Battle, you will earn a number of different rewards. The first reward you will receive is in the form of Premier Balls. Unlike other types of PokeBalls, Premier Balls are only given out at the end of Raid Battles, the same that you can use to then try and capture the Raid Boss you just defeated. The number of Premier Balls you receive varies depending on a number of different factors: what team owns the Pokemon Gym, what teams inflicted the most damage to the Raid Boss during the Raid Battle, and how much damage did your personal Pokemon inflicted during the Raid Battle. The more you did of eahc of these factors, the more Premier Balls you will receive.
After defeating raid battles, you will also a number of different free items for your efforts. Specifically, these items can include Fast TMs (allow you to change one of your Pokemon's Fast Attacks), Charge TMs (allow you to change one of your Pokemon's Charged Attacks), Golden Razz Berries (maximizes motivation if given to a Pokemon at a Gym, as well as greatly increases the odds of catching a Pokemon in a Wild Encounter), and Rare Candies (can be exchanged for a given Pokemon's Candy). (You can also receive a number of other basic healing items from Raid Battles.) The higher the Raid Battle Level you defeat, the more of these items you will obtain.