A good diet, training, and rest routine is the ultimate test booster. Don't worry about over the counter products, they are, generally speaking, a waste of money.
Also dude, its pretty much not a good idea to mess around with anti-estrogens either. They dont really do anything good, because you need estrogen to build muscle. A good diet, the basic essential supplements (which are protein, a vitamin, fish oil, creatine, and BCAAs) and rest are whats gonna make the most difference.
If you wanna look into the world of non-natural hormone replacement go into the steroid forum and start researching. There are some good OTC prohormones for making gains but they must be used with complete knowledge of their mechanisms and side effects.
Also, tribulus doesn't work, so dont bother wasting your money. Any effects you feel from it are just a placebo effect.
Bottom line, if you are 21 and 205lbs at 10% you definitely have room to grow and you DO NOT need a test booster because your natural test production is definitely at its highest dude.
Using
ZMA like you are is an awesome way to support your test production. But the difference is that that is a mineral supp while trib and everything else are not things your body actually NEEDS to make test.