Today’s little known opening is Saveilly Tartakover’s original rendition of the Catalan Opening. Tartakover liked to play 1.d4 Nf6 2.g3, which immediately puts Black on his own resources and has many transpositional possibilities.
The traditional argument against this early 2.g3 is that Black can blunt White’s bishop on g2 with …d5 followed by …c6 and …Bf5. But here too White has some interesting resources as the following game demonstrates:
There are a handful of modern players who like 2.g3, most notably the Russian GM, Vladimir Burmakin. And his games are worth a look if you’re interested in this move.