Ind-coherent sheaves
The category of ind-coherent sheaves is a small (but important) modification of the category of quasi-coherent sheaves, and appears in the statement of the Geometric Langlands conjecture.
As a source one can use Sections 1-5 of Gaitsgory's or Section 4 of Drinfeld-Gaitsgory.
Additionally, you can use Section 5 and Appendices A & B of this paper by Toly Preygel.