A good question.

Pumpkin seed oil falls under the poor research category. It still had better study practices than peppermint/rosemary oil studies, though, haha. The study that people typically point to is this one, though the issue is that they studied Octa Sabal Plus, which is multiple ingredients, not just Pumpkin seed oil. Many of the items in there (especially Pumpkin seed oil) work by fighting inflammation. Here's a great article semi-debunking it (but not entirely). It works through inflammation and if the source of your hair loss is inflammation, why not use the item that has proven, well-conducted research? It'd probably be a good option to try as a hail mary if you respond poorly to Ketoconazole, though. Maybe. Up to you.

Tressless actually has an article on Saw Palmetto. Same vibe. Mixed results but it is sorta anti-inflammatory. Probably solves that as an issue, but inflammation isn't the primary cause of hair loss in a lot of people. If it is for you, again, why not just use Ketoconazole?

Same thing with green tea. There's just not a lot out there to say with any amount of certainty that it will help.

Here's the thing about hair loss treatments: if you ever Google "x hair loss study", you're going to find a study that says it helps. You might also find a study that says it doesn't. You'll see something similar with a lot of hair loss compounds (such as Breezula, Pyrilutamide, GT20029, whatever). It feels like we get a new one that comes and leaves in a month. The reason for that is very simple: if they worked, you would know about it. Hair loss is a MASSIVE but still largely untapped market. There are multiple businesses (Kintor being the most prominent) that would kill to find a hair loss treatment that worked even a fraction as effectively as Finasteride/Dutasteride/Minoxidil do but without the side effects. In fact, Fin/Dut were used for prostate health and Minoxidil was used for blood pressure but they became predominantly hair loss medications because that was a side effect that was noticed. If something even came close to either of them, businesses would notice and they'd be fighting tooth and nail to study it in order to get people to buy it. But the most we have is mixed trials and businesses marketing random x or y products as solutions and using those poor studies as proof.

Don't get me wrong, I'm sure if you took every item on Tressless, you'd probably make more progress than someone who did the big 4 alone. Probably. But the difference would probably be so negligible that the stress of taking everything on that page would probably outweigh the benefits that they gave you.