R134A - It is similar to R12 and it is used as a replacement for R12 since R12 has been banned in 1996.
R402A - Used in low and medium temperature commercial refrigeration applications.
R407C - Replacing R22 in residential and commercial air conditioning applications since R22 has been phased out in new equipment in 2010.
R417A - A near azeotropic retrofit refrigerant blend for R22 direct expansion air conditioning systems. The best use case is in split air conditioning systems. It is an efficient cost-effective, non-ozone depleting HFC based refrigerant blend.
R438A - It is a retrofit for R22. It is a blend of five different refrigerants used for medium and low temperature refrigeration applications. R438A is non-flammable and has an ASHRAE safety group classification of A1. Its ozone depletion potential (ODP) is zero.
I would like to mention some old refrigerants that have been banned and phased out because of the environmental issues they were causing.
Refrigerants like R12, R500, R502, and R22 cause damage to the ozone layer in the stratosphere 7-30 miles above Earth's surface.