The word “professional”, particularly as the part of the name of any product. The bigger the typeface, the less likely professionals actually use the product.
I’m an IT guy. I came here to post just that. ANY e-mail that has the word “Kindly” in the first sentence is a scam, and a non-native English speaker.
“Please kindly buy me gift cards”
“Kindly do the purchasing”.
“Premium”.
“Pre-Purchase” for games.
Yeah, as in never Cash on Delivery…
That’s a good point. I see this in foreign scam/spam/phishing attempts frequently as well.
Homeopathy is homeopathetic.
What I find more scammy is when homeopathic things hide that they are homeopathic.
I know people who are aware that homeopathy is garbage yet had no idea that Zicam was homeopathic and took it, believing it was great for colds.
I was going to say the same: “kindly” is scam language
Wellness.
Don’t tell me you had to read all the way down to the word “modality” to figure out the email was a scam. 
Crystals. Herbs. Healing.
“Herbs charged with healing crystals” for a triple threat.
Also, in @Mangetout’s example, “Urgently proceed” plus pretty much any use of urgent.
“Kindly” is my second place entry. “Dear” is my first vote.
Tripler
‘Dear’ = immediate delete.
Beloved. Or any email from Mrs. _____. The only person I’ve ever heard introduce themselves as Mrs. So-&-so was a bride at a wedding, & that was because it was literally minutes old & she was being playful, as in, “Hi, nice to meet you, I’m Mrs, NewLastName”.
Warrantee
Unless it is a bill or a receipt just about anything with a $ sign in it.
And “chemicals”.
No, I like “kindly”. It was nicely used by an excellent lawyer in the one and only civil suit I’ve ever launched. It was basically in the context of “kindly do these things or we’re going to sue your ass to kingdom come”. It worked really well.
My word of choice is “free”. Hey, we’re a big profit-oriented corporation, but we’re giving you this stuff for “free” just because we love you. Take it, there’s no strings attached. We love you!
Where it stands out is someone claiming to be an American govt official or bank CEO/CFO or such yet using a word associated with former British colonies.
Muricans’ would use “please”.
ETA: Of course, the utter insanity of the scam itself should be a dead giveaway.
I think there’s a substantial distinction in meaning. “Please” has become a completely meaningless euphemism, whereas “kindly” still carries the aura of “I’m asking nicely and don’t want to be unnecessarily belligerent”.