The DR number, Diederich Rank, refers to the highest number in Diederich's frequency listing, which you can see here: Diederich Ranking.
DR 166. Fortis qui se vincit. ~ Note: As often, the antecedent of the relative pronoun is implied but not expressed: "Fortis (is) qui se vincit."
DR 166. Nihil non potest fortis animus. ~ Note: Note that here the double negative does make a positive: There is nothing a brave heart cannot do = a brave heart can do anything.
DR 169. O tempora, O mores! ~ Note: It probably makes sense to consider this famous saying to be an accusative of exclamation as well. You can read about these famous words of Cicero at Wikipedia.
DR 169. Mala vita, mali mores. ~ Note: The idea is that you can look at someone's life, vita, and judge that person's character, mores, by their life.
DR 169. Alia tempora, alii mores. ~ Note: This is another of those "aliud…aliud" sayings - the idea is that different times require different customs.
DR 169. Alii homines, alii mores. ~ Note: This is another of those "aliud…aliud" sayings: Some people act one way, other people act a different way.
DR 169. Suus cuique mos. ~ Note: This dative here is what you could call a dative of possession: each person (has) their own custom.
DR 171. Vocatus et non vocatus, deus est. ~ Note: Compare this saying in Erasmus's Adagia, 2.3.32: Vocatus atque non vocatus Deus aderit.
DR 171. Malus est vocandus, qui sua est causa bonus. ~ Note: To be "sua causa bonus" means to be good only for one's own purposes, for one's own advantage. This is one of the sayings attributed to Publilius Syrus.
DR 172. Homines sunt eiusdem generis. ~ Note: A genitive phrase can be used in the predicate, as here, to describe something, much like the English idiom, "People are all of the same type," i.e. we belong to the same type, the same species.