I am not that far into the game and have not really gotten more than a few systems past my starting one so this might just be a result of that. I probably have about 20-30 blueprints for varying things, hazard protection, mining speed upgrades, hyperdrive fuel chemicals, etc. I am starting to see quite a few duplicates though and am not seeing very many "unique" upgrades that do more than just upgrade the main things I already have. How many blueprints are in the game? Is it in the hundreds and I am just not that far or am I probably seeing everything I should expect to see for the rest of the game?
Some of the blueprints' text descriptions indicate that those are the best you can find for that function (e.g. mining laser combat effectiveness). Additionally, if you view your suit/ship/multi-tool inventory, the 4-swirl summary on the right shows how much you've upgraded various aspects of that thing (e.g. mining, combat, scan, grenade). So, if you apply all the blueprints you have but the swirl isn't full, that would seem to indicate you're missing some blueprints.
I've been getting duplicates for (literally) days now, but I've never found a blueprint for my ship's scanner. It seems silly that there would be a category for such a thing if there were no blueprints for it, so I can only assume it comes along later in the game. Same thing with the "Curiosity" section of the product construction menu -- there's nothing available for me in that section yet.
But just because you're getting duplicates doesn't mean you should stop grabbing them. (Though you could probably stop grabbing the multi-tool ones from the wall units ...) After dozens of dupes I recently found a product blueprint that allows me to make a boatload of money relatively easily. It's possible that it only dropped for me after reaching some milestone, but if so I have no idea what that milestone might have been. I've just been wandering around.