After 1.d4 Nf6 2.Bf4

2...b5!? is an idea

Analyzing 2...b5, a main line goes 3.Nf3 Bb7 4.e3 and now:

4...a6 5.Bd3 e6 or Nh5
4...a6 5.c4 bxc4/b4
4...b4 5.Bd3 e6/Nh5/c5
4...b4 5. a3 a5

The order which white plays Nf3 or e3 are interchangeable.

2...b5 is worth exploring, and would be interesting to see outside of blitz games at the top level. White may finally start to get out of their comfort zone with a non-standard pawn structure and black activity.

Based off of Caruana vs Vachier-Lagrave 2018 1/2-1/2, (blitz)

What do you think? White may decide to go on autopilot with the standard Nbd2, h3, 0-0. However, I believe that black's option to either attack the queenside or preserve the LSB is a powerful counter to the London's boredom.