These are heavy weapons that can give you the best idea about malware functionality, but may also take the longest time to master and work with. If you are unfamiliar with assembly, it is recommended to go through Chapter 1, A Crash Course in CISC/RISC and Programming Basics for x86/x64, first in order to get an idea of how it works. The list of known players is actually quite big, so let's split it into two rough categories—actual tools and engines (libraries).
Germany
Slovakia
Canada
Brazil
Singapore
Hungary
Philippines
Mexico
Thailand
Ukraine
Luxembourg
Estonia
Lithuania
Norway
Chile
United States
Great Britain
India
Spain
South Korea
Ecuador
Colombia
Taiwan
Switzerland
Indonesia
Cyprus
Denmark
Finland
Poland
Malta
Czechia
New Zealand
Austria
Turkey
France
Sweden
Italy
Egypt
Belgium
Portugal
Slovenia
Ireland
Romania
Greece
Argentina
Malaysia
South Africa
Netherlands
Bulgaria
Latvia
Australia
Japan
Russia