An ALF1 can still be created by our ARRI Look Creator (ALC), but the software is EOL and is not maintained since OSX 10.8.
There are 3rd party possibilities to create ALF1 files with:
 
Pomfort Livegrade Pro
The ALF1 functionality was removed from the Livegrade GUI, but it can still be made visible by importing this sample Pomfort Look File (*.plf). Select File -> Import Look as Shot -> Pomfort Look (plf).
 

Lattice
With Lattice it’s still possible to convert a 3D-LUT/Look and generate an approximation ALF1 *.xml Look file for the ALEXA Classic series. Select File -> Export Approximate -> Arri Look XML.
 

External LUT Box

It's also worth considering external 3D LUT boxes as an option:
 
AJA Color Box
Flanders Box IO 
Teradek COLR
TV Logic IS mini (former Fuji IS mini LUT boxes)