Most agents work with both buyers and sellers. But they almost always only represent just the buyer or the seller in each transaction. The responsibilities of agents change based on which side they are representing. Agents representing buyers typically help with searching, scheduling tours, negotiating offers, closing the transaction, and supporting their client after close. Seller's agents often focus more on preparing listings for sale, marketing listings, coordinating open houses and tours, and supporting negotiations and closings.
A buyer’s agent helps a buyer find, tour, offer on, and close on a home. Many new agents focus on buyers more than sellers. Often a buyer’s agent spends a substantial amount of their time helping their clients search for homes and schedule tours at homes of interest.
An agent representing the seller helps list a home for sale, market the home, and coordinate tours and open houses. Seller’s agents are often spending a large portion of their time helping prepare a home for sale, marketing the home, and coordinating tours and open houses to help a home move quickly at the highest price.
A listing agent is simply another term for the agent representing the seller.
Rental agents are often help with sales as well. But in some cases, they have different licenses or choose to focus exclusively on rentals. Many agents early in their career focus on rentals. Just like with sales, they can help the seller by representing the landlord or the buyer by representing the renter. The responsibilities are typically similar, but the process moves faster and the value of commissions are often lower.