I've tried quite a few over the years.
Here's a sample of the more recent:
1) MuscleTech Test HD - actually surprisingly useful for the money, especially if you can score a B1G1 deal. Won't get you snorting like a bull though.
2) GAT Testagen - probably the strongest I've encountered yet. Took a couple weeks to get going but when it did...look out!
3) AEN APE - surprisingly strong for a 2 cap/5 day a week formula. I really liked this pre-workout, stacks well with another booster for extra punch too.
4) IML Anabolic Matrix - used with LGD, seemed to do the job, really picked up after the third week so it would have been interesting to run another bottle, but I switched to...
5) IML Ultra Male RX - my current test booster. I definitely felt a drop off after Anabolic Matrix, but Ultra Male seems to be kicking in now.
Previously I've used TSN Natural T & it was ok, not great, but it did shine when I stacked it with Ronnie Coleman Testogen ( taken preworkout), it was actually too much after about 2 weeks, I had to back off as my female housemate at the time was getting nervous around me. I was panting like a madman! Testogen I like, it does more for me than straight DAA by a long shot.
Infinite Labs Cyclo Test was waaay underdosed - I see now they recommend you take double the dose. Haven't tried it that way, but it would want to be cheap as one bottle will only last 2 weeks at that rate.
Straight tribulus did jack all for me. I find it seems to work more synergistically with other natty booster compounds. Tongkat based products seem to give me a bit more kick too.