The one I got my best results is Traffic Swirl. It is a TE but has something different: You can earn TOKENS, even for free and use them to "bribe" leads to sign into your business. And it is fun to surf!!!
The other one is Leads Leap. A TE with a difference. you can even earn a few cents from your surfing and earn credits at the same time.
The ads you publish there have the advantage that MUST be watched for a few seconds, not like other TEs where you can go about your business while the ad is there and neve give it a look.
It has some useful ebooks and tools that are free. Here is one:
Have a look and see how they work without spending a dime.
There are the list building sites too.
I am in a few and like many other things in internet some are here today and gone tomorrow.
Up to this moment the ones that work best for me are
Aussie Mailer: You get a lot of mails to click and therefore to earn a lot of credits
Dragon Safe List: Very like the previous. It gives you fewer mails but has a fair account of solo ads with many points.
Bweeble is not bad either. Every few mails you get one that has many additional points and your account buils up very quickly
These are the ones that work best for me.
As they are free you can have a look and decide.