FORKED from original mod, https://mods.factorio.com/mod/ProductivityResearchForEveryone by Semenar

NEW

Rebalanced with a massive amount of customization options added:
Now you can control the science packs added for each 'tier' of the game. You can even control what defines a tier.
Default values I decided upon:
Early Game is 3 or fewer Science Pack types, those researches get Red, Green, and Purple science (added if not already present).
Mid Game is 4 to 6 science types, those get Red, Green, Blue, Purple, Yellow, and Agriculture added.
Late Game is 7-8 types, those get Red, Green, Blue, Purple, Yellow, Space, and Agriculture added.
End Game 9+ types, those get all but military added.

Remember, the types above are just types added if the algorithm didn't already have them, they're not added twice if they exist.
To compare, the original mod would generate iron plate productivity as a Red only science research, my version ensures that Red, Green and Purple are required.

Productivity research generated specifically FOR science packs get a special config option and get EVERY single science pack by default, no more cheesing the early game!
Obviously you don't have to enable this feature.
The Science Type number defining the tiers is also configurable as are the science packs added for each tier. I wanted to keep the original authors intention of making it as flexible as possible for future mod packs and TCs.
To make all but science research added by this mod take the "End Game" set of packs, just set all the tier config options to 0.

Config option to ensure all researches have a minimum time cost, set to 1 to ignore it. Defaults to 15. Some early game research can generate with 1 or 2 second steps, the config option ensures a minimum. Max value of this option is 1200...

This takes the original concept by Semenar and attempts to balance it while keeping the spirit of the original mod. Marathoners out there can even set the time cost up to 1200 seconds per step for researches that could actually take years to complete.

I tried to make the default balance push people to pursue massive science builds. Ag science in all but the Early tier pushes people to have robust Gleba builds.