I am mid-50s and had a schoolmate who went by Dickie. That’s the only one of my generation I can recall.
Former MLB shortstop Dickie Thon is 55.
I wouldn’t count Dick Togo, since that’s just his ring name. It’s sorta like if someone said “hey know anyone named Ron” and you bring up Ron Burgandy.
I looked him up when first reading this thread, and it seems he shot himself. I’m sure there’s a morbid joke using his name and method of death as puns someone could make in there somewhere.
Now that you mention it, I know of a woman named Dikki. That’s her legal name.
There was a kid named Richard, went by Dick, a year behind me in HS. He’d be about 52 now. I don’t know if “Dick” is still his nick.
Other than that–all the Dicks I know are 70+.
As are most of the “famous” Dicks: Dick Allen, Dick Van Dyke, Dick Cheney, Dick Durbin, etc.
Isn’t Dick Clark forever young?
(Despite having died of old age, that is.)
My father’s given name is Richard; he goes by Dick. He just turned 80 last week.
I know several other Richards – the only one who goes by Dick is in his 60s. All of the others (including my cousin, who is my age (48)), go by either Rich or Rick.
I have a cousin named Richard who goes by Rick. He’s in middle school. So… we missed a golden opportunity to have a really young Dick in our family.
I know one who is my age or perhaps a couple of years older–so early 40s, maybe 45 at the outside.
Is anybody actually named Dick? As in, that’s the actual name printed on the birth certificate? I’m pretty sure 99.9% percent of the people are, or were, just using that name as short for Richard.
Youngest one I remember was probably in his mid 40’s a couple decades ago. (Pointless aside: When I mentioned to a therapist that I’d spent the night with a man, she asked me what his name was. When I said “Dick” she almost fell off the chair laughing.)
It exists (as “Dik”), but is certainly not very common. In Dutch it means fat, and not in a slang way, it’s just the regular word for fat. It would be exactly like being called Fat in English, so it’s not a common name. I’ve never met anyone called Dik. (ETA I have met old people called Dick (English))
An old-fashioned, formerly common name was Cock. I work with a guy in his 60s called Cock, which is always fun to explain abroad. Honestly I don’t really know why he doesn’t just pick something else for use internationally. It’s so awkward.
Dutch Bob does come from Robert, I’m not sure why you think it doesn’t? It’s not exactly short for it with any regularity, people called Robert aren’t called Bob for short, but as I understand it it’s where the name comes from.
Dicky Lyons Jr. finished HS in 2004, so that would probably make him 27/28 years old.
Most American parents don’t want to publicize their kids widely.
So there’s probably a lot of little Dicks running around, and only their friends and family know about them. 
Elliot Stabler’s son on SVU is named Dickie. It always strikes me as especially unrealistic; for a man to call his boy not just Dick but little Dickie- so diminutive!
He started going by Richard when he hit high school and typically Elloit was in denial: “His name’s Dickie, dammit!”
Yes, I know these aren’t real people.
Just my opinion: “Dickie” and its variants don’t count. But I’m not the OP.
Personally, the youngest I could think of is my own state’s prominent attorneys, Dick Harpootlian. He actually held some elected office at some point, but I always thought it was funnier that his last name had ‘poot’ in it. But I’m easily amused. He’s probably in his early 60s.
I also knew a woman who was called ‘Dick.’ Not her real name, but it did begin with a “D.” She’d probably be about 80 now if she were still alive.
It could be an allusion to the show’s creator, Dick Wolf.
I was named after my dad’s best friend in high school, who apparently went by “Richard” in school, but as an adult started going by “Dick”. I think he died a few years ago, but he’d be 69-70 now were he still alive.
I started going by “Rick” when I was 13-14, and changed the spelling to “Rik” when I was 17. I never once considered going by “Dick”. I’m 47.
Just for fun, I did a search of the SSA’s most popular baby names. Going back 100 years, “Dick” (as a given name), fluctuates around from ~140-500th most popular, until the 1960s. The last year it appears in the top 1000 is 1968. If you know a Dick (not Richard), he’s probably at least 50 years old.
Wikipedia doesn’t have any pages for Dicks, just Richards, and of those that are known as Dicks, it’s the usual older crowd, Cheney, etc.
IMDb lists quite a few Dicks, most older or already mentioned (like Wolf). Two possibly young ones: Dick ‘Skip’ Evans, who does stunt pilot work. No birth year given and first credit is 1988. But note that he goes by “Skip”. And Dick Ward, who had a small role in The King’s Speech. The latter is poss. British, where the name still seems to have a hold. Again, no birth year and first credit is 1996. Neither has a lengthy IMDb resume.
There are a lot more Dicks listed, but you’re getting into really obscure territory.
I don’t know any Dicks younger than 60. Plenty of Ricks and Riches and Richards, though.