Razr X is the center club in the Razr family (seven different iron models) that came out in 2012.
Golf Digest rated the RazrX as the GI iron of the Razr line. It corresponds to the X20 of a circa 2008 (except the X20 was rated as SGI). I tried the RazrX during a clubfitting last spring, and it basically tied in performance data with my X20 Tour irons. So, no sale.
Stock shaft for RazrX is the Uniflex, which not everyone likes. Other shafts are available if you ask.
RazrX is being edged out by the X Hot irons.
The RazrX NG (new grooves - odd designation, everything is NG these days) is a continuation model meant for the $400 pricepoint market. If you look on Callaway Preowned, you'll see a small number of X18R (reissue) and X20NG models available, previous lag-year variants for the $400 market. Callaway already has the R&D and name-recognition paid for, so why not leverage the model for another year as an economy set?
Razr HL (high launch) fits in the old Big Bertha niche of super-helpful clubs. Stay away from HL if you already get good height on the ball. I'm not sure HL is still a production model.
Both RazrX and HL versions offer iron-replacement hybrids you can blend into the low end of the set. (Neither model makes a 3 iron.)
You gave no clues on current bag mix or HDCP, so I'm not sure what to advise you to hit.