In addition to standard email ads on these sites you also can use solo ads, login ads, banners, texts, spot ads and footer ads. Since most members don't use all these other ways to promote, they are less saturated than just the safelist emails.
I have found the best way to get your message in front of the most responsive safelist members is to use login ads. Your ad is featured for a particular day or week on the site. During that time, every member who logins will see your site before they enter the member's area.
However, at most traffic sites Login Ads are a paid option.
Fortunately, there are some traffic sites that provide this opportunity at no cost!
One of them (and the best one) is Mister Safelist.
At Mister Safelist, the Featured Site will be shown once per day for a full 20 seconds to every member when they login to the site.
To book a featured site, go to "Site of the Day" on the navigation menu and you'll see a special page where you can bid credits to become the featured site.
Bid using your credits. If you have the highest bid at midnight EST on the day before, you will win the featured ad for the next day.
I recommend that you upgrade because upgraded members get more credits and have more chances to outbid their competition.