There are several website brokers that can assist with the sale of a novelty only diploma website that generates over $100,000 in sales a year. Here are a few reputable options:

1. Flippa: Flippa is one of the largest online marketplaces for buying and selling websites. They have a dedicated section for selling established websites and provide a platform for sellers to showcase their sites to potential buyers. Flippa offers various listing options and has a wide reach, attracting both individual buyers and investors.

2. Empire Flippers: Empire Flippers is a trusted website brokerage firm that specializes in selling profitable online businesses. They have a rigorous vetting process to ensure the quality of the listings and provide comprehensive due diligence reports to potential buyers. Empire Flippers offers personalized assistance throughout the selling process and has a large network of qualified buyers.

3. FE International: FE International is a leading website brokerage firm known for its expertise in selling high-value online businesses. They have a team of experienced brokers who work closely with sellers to maximize the value of their websites. FE International offers a personalized approach, including thorough valuation, marketing, and negotiation services.

4. Quiet Light Brokerage: Quiet Light Brokerage is a boutique website brokerage firm that focuses on selling established and profitable online businesses. They have a team of experienced brokers who provide personalized guidance to sellers throughout the entire selling process. Quiet Light Brokerage has a strong track record of successfully selling websites in various niches.

Before selecting a website broker, it's important to consider their reputation, track record, fees, and the level of personalized assistance they offer. It's also advisable to reach out to different brokers and have initial discussions to assess their understanding of your business and their ability to market it effectively.

Additionally, it's worth mentioning that seeking advice from professionals such as lawyers or accountants who specialize in online business sales can also be beneficial, as they can provide guidance on legal and financial aspects of the transaction.

Note: It's always recommended to conduct your own research and due diligence when selecting a website broker, as the suitability and effectiveness of their services may vary based on individual circumstances.