Here's what I believe the frog fractions timeline to be:
Frog fraction game of the decade edition (because it is a remake of frog fractions and the first game is officially first), frog fractions 2 hidden in Glittermitton Grove (also including the arg itself) (officially here in the timeline), Glittermitton Grove (officially here in timeline), Hop's iconic cap GotDE dlc (officially here in timeline), frog fractions Game of the Decade Edition (specifically after the secrets update)(I'd also guess that it is with the dlc hat equiped), and Gordy and the monster moon (no real reason although I don't think it's a prequel)

I don't know where to put the official frog fractions 2 & glittermitton grove guide
I probably also forgot something else
Unless someone objects I believe this is the correct order to play the games