A Man Is Not a Virgin - Particularly in Red Glove it's implied that Cassel's mother uses her powers to get many various girls to be attracted to him. Also, in a Dream Sequence he sees all his previous girlfriends who are all angry at him, because he used them. And there are many many many of them.
Ban on Magic - Magic has been illegal in the US since the 1930s. As with Prohibition, this lead to the rise of criminal syndicates built around an underground trade in magical services and the use of magic to aid in various criminal enterprises.
Being Evil Sucks - Growing up in the mob, being a con artist and being a secret assassin have led to Cassel being ridden with self-loathing and paranoia.
Demoted Memories - In Red Glove, Cassel realizes that something he remembers as a scene from a movie is an actual memory that Barron tampered with.
Differently Powered Individual: People with magical powers are commonly called "curse workers" or simply "workers"; the Technobabble term is "hyperbathygammic" or "HBG". "Heebiejeebies" is a somewhat derogatory term derived from the latter. Archaic terms include "theurgists" and "dab hands".
Dysfunction Junction - Cassel's family, due to both their criminal lifestyle and the effects of blowback.
Empathic Healer - Physical workers can heal injuries and cure or mitigate diseases, but the blowback makes them weak and sick.
Equivalent Exchange - Blowback works like this. The more you use your power, the more you're affected in the same area. For example, a luck worker that constantly decreases the luck of others will end up unlucky themselves.
Evil Parents Want Good Kids - Cassel's grandfather laments not having kept his daughter out of the mob. By contrast, said daughter actively worked (in every relevant sense of the word) to initiate her own sons into the life.
Fantastic Racism: The general public fears workers due to their power and the strong connection between magic and organized crime, to the point that everyone takes it as a given that the mandatory hyperbathygammic testing law, if passed, would lead to workers being denied jobs and housing.
For Your Own Good - Everyone who was involved in hiding Cassel's power and assassination history from him insists that they did it to protect him.
Missing Mom - Subverted. Cassel's mom is absent for most of White Cat, due to being in prison. It doesn't seem to change her relationship with her children and she is out of prison at the end of White Cat and in Red Glove.
Motive Rant - Barron has a small one near the end of White Cat.
Save the Villain - Cassel to Barron and to some extent Phillip at the end of White Cat.
And for Barron again at the end of Red Glove, considering he could have left him to the police.
Soapbox Sadie - Daneca Wasserman, who proudly displays buttons expressing her feelings on various causes on her bag, leads the Wallingford branch of a worker rights youth group, and scolds Cassel for his indifference to politics.