Other than the Cartel stuff, some of the pieces from the IA Battlemaster gear kind of sort of looks like heavy armor in my opinion. Also there are some custom Marauder boots, helmets, and gloves which looks like heavy armor.
Also, the Legacy gear for both factions which were quest rewards in the Rakghoul event looks like they could be BH/heavy armor gear.
Also those butt-skirts that are on some gear looks inspired by Mandalorian gear:
The most important thing in my opinion is just to look as bada** as possible, there has been many different Mandalorian looks in Star Wars.