i get my stuff normaly from a local Hardware Store. The brand-names may vary (Nigrin, Presto, MTT, Polikor, AutoK, Supernova....) Search for something that normaly fills Dents in the vehiclebody of your car. But stay sharp. There are mostly two types of fillermass. Stiff-Filler mass (normaly yellow or green in color) and a plast-fillermass (same thing but flexile and wont crack that easy - mostly black or grey in color).
I wish i could help you more but thats all i know.
Thats the tricky diffrence between Europe and US.
The US-market is way more standarized while in Europe EACH COUNTRY has for one produkt several providers that underquote each other. (Except that most products come from the same factory and the Brands just swap XD ). For the whole Armor thing i've learnt that Resin has about 7 and may more diffrent names and synonyms in german, for example (Gießharz, Polyurethanschnellgießharz, Schnellgießharz, PU-Harz, Epoxidformharz.... ). And I guess in countries with a slawic-language the Produkt names are a thing of their own either.