What do I consider an "Overlooked Nootropic"
Chamomile as a superior alternative to L-theanine
Chamomile is prepared as a tea, which you can buy in bulk or even get in retail for super cheap. If you work in an Office chances are they'll stash Chamomile tea somewhere by the Keurig Machine (Coffe Station).
Additionally, Chamomile offers the following benefits that L theanine doesn't.
Removes estrogen, boosts Testosterone
Positive evidence for Anti-Cancer effects
Apigenin is a flavanoid that has a high selectivity to invoke selective apoptosis of cancer cells in vivo. 
Or in other words... reduce oxidative stress -> that simply means whenever your body is put into a state of stress... this could be from alcohol, over-exercise, over-work/fatigue, poor diet and lifestyle choices, or drug abuse... Apigenin will help reduce the damage done to your body.
Carcinogens are chemicals that increases the likelihood of Cancer. E.g. smoking cigarettes, prolonged unprotected exposure to the sun, eat trans-fats etc.... Chamomile acts as an agent to detoxify (via inducing a dose-dependent phosphorylation of extracellular signal-regulated protein kinase) your body from these foreign cancer causing agents.
Anti-inflammatory should be self explained. Sometimes your body gets riled up when it doesn't need to because it always thinks its under attack. This has a deleterious (bad) effect long term and a lot of our health choices are geared toward lowering inflammation for good mental and cardiovascular health.
As a programmer and gym goer...
As someone who enjoys an occasional beer (favorite is Blue Moon), it's also nice knowing that Chamomile can counteract any extra estrogen buildup you get from beer. I actually notice a physical difference because my skin doesn't break out and I don't feel bloated in my face. (2 very common side effects of having high estrogen in men).
Last but not least it's sort of expected to push your body to the limit in your 20's. Maybe once a week I will pull an all nighter which really could throw your body off. In those moments I definitely make an effort to drink as much Chamomile as possible.
In that article it reported: " significantly decreased cortisol production (by 47.3%) at a concentration of 25 microM without any significant cytotoxic effects or changes in cell number.".
That's huge. 47.3% less cortisol - almost half. Any damage I take from the all nighter is halved to what it could have been. This keeps me going strong and illness free at my competitive rate.
 Selective growth-inhibitory, cell-cycle deregulatory and apoptotic response of apigenin in normal versus human prostate carcinoma cells. http://www.ncbi.nlm.nih.gov/pubmed/11573952
 The chemopreventive bioflavonoid apigenin modulates signal transduction pathways in keratinocyte and colon carcinoma cell lines. https://www.ncbi.nlm.nih.gov/pubmed/14608117
 The effects of plant flavonoids on mammalian cells: implications for inflammation, heart disease, and cancer. http://www.ncbi.nlm.nih.gov/pubmed/11121513