Deleuze is the constructive figure among the French theorists — less interested in dismantling the tradition than in building an alternative to it out of the philosophers it had marginalized.
His central move is to make difference primary. Western metaphysics, on his reading, treats difference as a relation between things that are first identical to themselves; Deleuze inverts this, treating identity as a temporary effect of underlying processes of differentiation. From this follow the concepts the work is known for: the rhizome, a structure with no center and no hierarchy, against the tree of classification; the assemblage, in which components function together without forming an organic whole; becoming rather than being as the basic category.
The political work is the two volumes written with the psychiatrist Félix Guattari. Anti-Oedipus (1972) attacks psychoanalysis for reducing desire to a family drama of lack, arguing instead that desire is productive and social from the start, and that capitalism has an extraordinary relation to it — decoding and releasing flows that older orders had bound, then recapturing them for accumulation. A Thousand Plateaus (1980) develops the vocabulary of smooth and striated space, the war machine, and lines of flight.
The influence has gone in incompatible directions. The horizontalist left took the rhizome and the critique of centralized organization; accelerationism, including its reactionary wing, took the account of capitalism as a deterritorializing force and argued for pushing it further rather than resisting it. Deleuze himself was a Spinozist and a man of the left who thought philosophy's job was the creation of concepts, and would have recognized only some of what has been done with his.