Adcash

Adcash supports both advertisers and publishers, offering a variety of formats including banner, interstitial, in-page push and pop-under ads. There is no minimum traffic requirement for publishers.

Adfly

Adfly is a URL shortening service that pays you for visitors that click on your shortened links.  They also sell bulk traffic which you can have targeted to specific regions or countries.

Clickadilla

Clickadilla provides advertisers and publishers with a variety of ad formats including in-stream video, web push, popunder, native ads and banners.

Fiverr

Fiverr can be a great place to find traffic providers that are in different niche markets and some that have unique sources of traffic that a larger company may not have the time to focus on, as well as a great place for those selling traffic to make their first sales.  They have a review system which helps to weed out bad providers and it is wise to avoid listings with previous mediocre or poor reviews, and there are also a large number of people re-selling traffic bought from a wholesaler on Fiverr, and with that in mind you will want to look for sellers that give a good background to their traffic source and who appear to be the actual owners of the traffic source.

Horizon

Horizon offers guaranteed website traffic, e-mail marketing, banner advertising and hosted services.  Their website traffic can be purchased as country-specific, specific to a niche category or a combination of both, as well as e-mail lists that they can also send the mail for if you do not have your own servers.

Media Mister

At Media Mister you can buy followers, likes, views and subscribers from every major social media network.

Propeller Ads

Propeller Ads offers a range of traffic sources including pop-under, interstitial, banner ads and push notifications.

For those looking to monetize bulk redirect traffic, Propeller Ads offers a direct link that can act as a catch-all to monetize unused traffic from any of your domains at once.

Semrush

Semrush is a powerful and easy to use SEO, content marketing, competitor research, PPC and social media marketing from just one platform.  With their free account you can do a limited number of keyword lookups and other site analytics per day to meet basic keyword research needs.

Serpclix

Serpclix provides real human visitors who are paid to do particular searches and then click on your site.

Top Of The Results

Top Of The Results provides SEO/CTR traffic that will come from searches based on a keyword you select to improve the click-through ratio and on-page time for those keywords, and includes features such as scrolling and fine-tuned control of traffic behavior.

Ubersuggest

Ubersuggest is a great tool for finding keyword variations that get the most traffic, offering a keyword ranking overview for individual sites as well as general keywords.  You are allowed three lookups per day without registering, and a 7 day free trial is available.

Verytraffic offers a free plan of 6,000 page views per month of automated traffic. Paid packages are also available that offer additional options in controlling the traffic delivery.

Winterplay Studios Inc.

Winterplay Studios offers multiple-keyword targeted traffic traffic to drive niche traffic to your site.

Udimi
Website

Udimi is the world's largest solo ad marketplace, which offers a place for sellers to post their serviices and for buyers to purchase advertising, which is all handled through a secure escrow through Udimi.  Udimi also offers a nice affiliate interface and resources for those wishing to promote it.