Curious to know if Broms produce seeds? Just looking for another way propagate.
The short answer is yes, but it's not that simple. First, only species will come true from seed (hybrids will give you a jumbled mix of results), and many are not self-compatible, meaning they will not set seed unless you pollinate them from an outside source. This would have to be a different clone of the same species if you want them to be true. There are many that will set seed on their own, however.
You can use the forum search engine on the bottom of the menu page and type in "seed" for a whole range of information on the topic, from seed sowing techniques to hand-pollination, and a whole lot of discussions of hybridizing. There is much too much to reprise it all here.
See in numerous posts here, you are the Brom expert. :0)
So, what should I look for on a brom to see if it has seeded?
I'm no expert, I've just been at it a while. ;-)
As for what to look for, it depends on what type of brom you have. For berry-forming types like Aechmeas, Porteas, Billbergias, etc. the ovary will swell up and often turn color when the seeds inside are ripe. Look for blue, purple or black fruits, although on some species they may be red or yellow. Neoregelias also form berries, but they're much harder to see down in the cup, and most of them won't turn color. A gentle tug will tell you if they are ready to harvest.
Vrieseas, Guzmanias and Tillandsias form hard seed pods instead of berries, and they will pop open and scatter the fluffy seeds to the wind when they're ripe. Best to keep an eye on those so you don't miss them, but it can take anywhere from 6 months to a year for these types to ripen, and the seedlings are similarly much slower growing than the berry types. Unless you have unlimited patience, I wouldn't even attempt growing Tillandsias from seed. You can probably figure on at least 8 years before you'll get a blooming plant that way. Neos, in contrast, will mature in 2 to 3 years, and Bills and Aechmeas may be even faster.