There are several different types of listing contracts, but very few of them are used. The "Exclusive Right to Sell" is the most common, but there is also the "open listing," the "one-time show", and the "exclusive agency listing".

By working with me you have options on how you can save potentially thousands of dollars as part of an "exclusive right to sell" agreement.

Open Listing
People trying to sell their home by owner who are also willing to work with real estate agents mostly use the "open listing". Basically, it gives a real estate agent the right to bring buyers around to view your home. If their client buys your home, the agent earns a predetermined fee or commission. There is nothing exclusive about an open listing and a home seller can give out such listings to every agent who comes around.
For that reason, no agent is going to market your home or put it in the Multiple Listing Service (MLS). If your home fits the criteria for one of their clients, and it is convenient, they may be willing to show it to their client. That is all an "open listing" is good for.
One-Time Show
A "one-time show" is similar to an open listing in many respects. It is most often used by real estate agents who are showing a FSBO (for sale by owner) to a client. The home seller signs the agreement, which identifies the potential buyer and guarantees the agent a commission should that buyer purchase the home. This prevents the buyer and seller from negotiating directly later and trying to avoid paying the agent's commission.
As with an open listing, agents will not be spending money on marketing your home and it will not be placed in the Multiple Listing System.
Exclusive Agency Listing
An "exclusive agency" listing allows an agent to list and market your home, guaranteeing them a fee or commission if the house sells through any real estate agent or company. It also allows sellers to seek out buyers on their own.
This is not a popular type of listing agreement. The reason is that there is not much incentive for agents to spend money marketing your home. If you come up with your own buyer, they have spent money they cannot earn back through the real estate fee or commission. Plus, it is too easy for a greedy buyer to go around the agent and negotiate directly with the seller.
If you find an agent willing to accept such a listing, do not expect too much from them. They will probably just place it in the Multiple Listing Service and sit around to see if something happens. A good agent would never accept such a listing, and you probably want a good agent.
Exclusive Right to Sell
Giving a real estate agent the "exclusive right to sell" your property does not mean that there will not be other agents involved. Your agent is the listing agent and part of his or her job is to market your home to other agents who work with buyers. Those agents will show your home to their clients. Regardless of who sells the home, even if you sell it yourself to a friend at work, your listing agent will earn a fee or commission.
An exclusive right to sell is the only type of listing an effective real estate agent will accept. This is because they have a reasonable expectation of earning back any money they spend on promoting and marketing your property. By working with me you have options on how you can save potentially thousands of dollars as part of an "exclusive right to sell" agreement.